Solar Seminar home page (FY2019)

Solar Seminar (13:30-15:00 Monday, Room 504 5th floor building 4) Access

Next presenters

Date	Time	Section	Speaker	File
12-23	13:00-14:00	main	Y. Tomino	upload or download
01-14	10:00-11:30	D3 practice	C. Denis	upload or download
	12:30-14:00	D3 practice	A. Tei	upload or download
01-27	13:00-14:30	M2 practice	Y. Kotani	upload or download
	14:30-16:00	M2 practice	K. Kihara	upload or download
	16:00-17:30	M2 practice	D. Yamasaki	upload or download

Please upload your presentation file!!

Date	Section	Speaker	File
10-07	main	Y.W. Huang	upload or download
10-07	short	S. Nagata	upload or download
10-21	short	S. Ueno	upload or download
10-28	main	A. Tei	upload or download
12-02	short	K. Nishida	upload or download
12-09	main	N. Kimura	upload or download

For Speakers

Presentation time for speaker is: main : 40 minutes as a guide, and 20 minutes discussion.
short : 20 minutes as a guide, and 10 minutes discussion.
Contents of talk are: main : about your study
short : review of recent interesting paper and share information of recent study of the Sun.
Language of slide and talks: Master cource students : Language of slide and talk could be Japanese
Doctor cource students and over : Slide must be English, and talking language could be Japanese
(If those who could not understand Japanese attend the seminar, it is preferable that you talk in English)
Title and Abstract: Please send the title and abstract of your presentation by the day before.
Presentation files: Please upload your presentation files by the start of the seminar.
If the presentation file is very big, please zip the file before uploading.

For Audiences

Honoring speakers: Plase clap your hands as a closure of a presentation to express your respection to a speaker.

For everyone

Publication sharing: Please send a copy of the submitted version of any paper on which they are working to the zasshikai mailing list just after submission

Useful webpage list for solar observers.

Date		Name	Title	Abstract	File
10-01	D3 presentation	H. Hayakawa
10-07	main	Y.W. Huang			MB
	short	S. Nagata			MB
10-21	main	T. Sakaue	Disappearance of taller spicules and drastic decrease in wind's mass loss rate in the weak magnetic field	Solar spicule and wind are the manifestations of solar magnetic activity. Their kinetic and thermal features are deeply involved with the magnetic field configuration in the solar atmosphere. Alfvén wave is responsible for the energy transportation in the magnetized atmosphere, and its propagation is affected by some non-linear processes which is crucially important to launch the spicule or drive and heat the solar wind. To understand the causal relationship between the magnetic field configuration and the resultant features of solar spicule or wind through investigating the non-linear processes of Alfvén wave, we performed the one-dimensional Magneto-Hydrodynamics numerical simulation. In this study, we consider the several magnetic flux tubes with the different field strengths, and investigate the dependence of typical spicule height and solar wind’s mass loss rate on the magnetic field configuration. The simulation results show the disappearance of taller spicules than 10 Mm and drastic decrease in solar wind's mass loss rate (down to ~ a few x10^{-15} M_\odot yr^{-1}) in the case of weak magnetic field. We will discuss these phenomena is caused by the highly non-linear Alfvén wave in the chromosphere.	pdf 40MB
	short	S. Ueno	Which wavelength of solar UV has the strongest influence on the ionosphere?	As one of subjects of the PSTEP project, we are trying to reproduce long-term solar UV variation that has influence on the ionosphere by using full-disk solar chromospheric images. However, we don't know which wavelength of solar UV has the strongest influence on the ionosphere. For this question, different geophysicists give different answers... Therefore, at present, I am investigating actual long-term relationship between one of physical parameter of the ionosphere and solar UV irradiance at various wavelengths. The ionospheric physical parameter that I use is "geomagnetic solar quiet daily variation (Sq)" 1). On the other hand, solar UV irradiance is obtained from several database, such as FISM, DeLand Composite SSI, Ly-alpha Model SSI, and so on 2). I will report present results in this seminar. References: 1) https://ui.adsabs.harvard.edu/abs/2017SSRv..206..299Y/abstract 2) http://lasp.colorado.edu/lisird/	MB
10-28	main	A. Tei	IRIS Mg II Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole	The solar chromosphere is dynamic and full of fine structures. Among them, spicules are long, thin, dynamic features which jet out ubiquitously from the solar surface, and connect the photosphere to the corona. However, the physical mechanism of spicules and their essential roles related to energy and mass transport is unclear. We investigated the off-limb spicules observed in the Mg II h and k lines by IRIS in a solar polar coronal hole. We analyzed the large dataset of obtained spectra to extract quantitative information about the line intensities, shifts, and widths. The observed Mg II line profiles are broad and double-peaked at lower altitudes, broad but flat-topped at middle altitudes, and narrow and single-peaked with the largest Doppler shifts at higher altitudes. We use 1D non-LTE (i.e. departures from Local Thermodynamical Equilibrium) vertical slab models in single-slab and multi-slab configurations to interpret the observations and to investigate how a superposition of spicules along the line of sight (LOS) affects the synthetic Mg II line profiles. The used multi-slab models are either static, i. e. without any LOS velocities, or assume randomly assigned LOS velocities of individual slabs, representing the spicule dynamics. We conducted such single-slab and multi-slab modeling for a broad set of model input parameters and showed the dependence of the Mg II line profiles on these parameters. We demonstrated that the observed line widths of the h and k line profiles are strongly affected by the presence of multiple spicules along the LOS. We later showed that the profiles obtained at higher altitudes can be reproduced by single-slab models representing individual spicules. We found that the multi-slab model with a random distribution of the LOS velocities ranging from -25 to 25 km/s can well reproduce the width and the shape of Mg II profiles observed at middle altitudes.	MB
	short	A. Asai		•Travel Report : Visit the MUSER site (2019-July-21~24) •Paper Introduction: Chen, Xingyao, Yan, Yihua; Tan, Baolin; Huang, Jing; Wang, Wei; Chen, Linjie; Zhang, Yin; Tan, Chengming; Liu, Donghao; Masuda, Satoshi, “Quasi-periodic Pulsations before and during a Solar Flare in AR 12242”, 2019, ApJ, 878, id.78	pdf 18MB
11-11	main	K. Kihara	Solar Flare Prediction with Image Recognition, Classification of Sunspot Complexity	A solar flare is an explosive process that releases magnetic energy on the Sun. Solar flares and their accompanied phenomena are crucial problem for space weather, so it is necessary to predict solar flares before their occurrences. Recently, machine learning techniques have been applied to the problem of solar flare prediction. Our group has been studying this using machine learning and image recognition. In order to construct a reliable flare prediction model, we are now carrying out the classification of sunspot complexity. By using the sunspot classification model, it is possible to improve the accuracy of solar flare prediction. In tomorrow's main talk, I will talk about the current status of our work.	pdf 11MB
	short	T.T. Ishii	B1.3 flare observed with Sartorius & SMART, on 2019-Nov-05, in NOAA 12750, belongs to Solar Cycle 25.	B1.3 flare observed with Sartorius & SMART, on 2019-Nov-05, in NOAA 12750, belongs to Solar Cycle 25. Report at Zasshikai short, T. T. Ishii Sartorius at Kwasan, Observer: M. Kamobe SMART at Hida, Observer: K. Otsuji Sunspot Sketch 2019/11/01 and report, by A. D. Kawamura	pptx 9.3MB
11-18	main	D. Yamasaki	Polarization Calibration of the Solar Magnetic Activity Research Telescope (SMART)-T4	The Tandem Etalon Magnetograph (TEM) is one of the 4 telescopes of the Solar Magnetic Activity Research Telescope (SMART). TEM is a filter magnetograph, which scans 4 wavelength points around 630.25 nm. TEM aims to obtain vector magnetic fields on the solar photosphere with a spatial resolution of 0.5-1.0 arcsec. A polarimetric sesitivity of 5*10^-4 is achieved for each wavelength point with integrating 675 images in 20 sec (Nagata et al. 2014). In this study, we performed the end-to-end polarization calibration test and evaluated the polarimeter response matrix of TEM in order to suppress any artificial polarization from crosstalk among Stokes vectors under the statistical noise over TEM's field of view(FOV). As a result, we found a significant spatial distribution through TEM's FOV in some components of TEM's response matrix. Then, we investigated a polarizing beam splitter's polarization property and found a circular diattenuation, which may caused by the stress on PBS, with spatial distribution through TEM's FOV. In today's talk, I am going to introduce TEM's polarization observation and the experiments of the calibration.	pdf 17MB
	short	K. Otsuji	The Reversal of a Solar Prominence Rotation about Its Ascending Direction during a Failed Eruption	I will briefly introduce the following paper: "The Reversal of a Solar Prominence Rotation about Its Ascending Direction during a Failed Eruption" (https://ui.adsabs.harvard.edu/abs/2018ApJ...864L..37S/abstract), in which a failed filament eruption occurred on 2010 December 10, showing counter-clockwise rotation in the eruptive phase, followed by clockwise motion in the falling phase.	pptx 40MB
11-25	D2 interim report	K. Namekata	恒星の巨大黒点及び恒星スーパーフレアの発生過程の解明に向けた観測的研究	太陽/恒星フレアとは、太陽/恒星表面で起きる突発的な増光現象のことである。近年、太陽型星の長期間観測から、太陽によく似た星では「スーパーフレア」と呼ばれる巨大フレアが起きていることが明らかになり(Maehara et al. 2012)、太陽及び(惑星を持つ)恒星における極端現象が注目されている。私は、恒星スーパーフレアを理解するため、(1)そのトリガーとなる巨大黒点はどのように生成するのか？(2)恒星(スーパー)フレアの放射メカニズムは何か？といった点を明らかにする研究を行なっている。(1)では、恒星黒点の生成・消滅率が、太陽黒点のスケーリング則で説明できることを明らかにした(Namekata et al. 2019, Namekata et al. submitted)。これは、太陽黒点と同様に、磁気浮上により生成し、表面対流によって拡散していく描像を支持する結果である。(2)では、2019年に完成した京都大学岡山3.8mせいめい望遠鏡を用いて、恒星フレアの連続分光・測光観測を行なっている。観測されたスペクトル形状や、波長ごとの放射強度の比の時間変化から、フレアによりエネルギー注入量が変化することや、エネルギー分配がフレアの大小で異なる可能性を発見した。本発表では、これまで博士課程で行なってきた上記の研究の進捗状況と、今後の博士課程における研究の展望を報告する。
12-02	main	Y. Kotani	Numerical simulation of photospheric anemone jets and their influence on the upper atmosphere	Jets phenomenon with a bright loop in their footpoint have been observed in the solar corona and chromosphere and these are called anemone jets.Anemone jets have a spatial scale difference of 10 to 1000 times between the corona and the chromosphere, but they can be explained in a unified way bu magnetic reconnection. From the scale universality of magnetohydrodynamics(MHD), we can expect anemone jets of about 100 km exists even in the solar photosphere. However, it is not obvious whether a jet can be generated by releasing magnetic energy by magnetic reconnection even in the photosphere where magnetic energy is not dominant. In addition, MHD waves generated from photospheric anemone jets may contribute to the chromospheric heating and spicule formation, but no one knows the answer. To answer these questions, we perform 3D MHD simulation including gravity with the solar photospheric parameter. As a result of the simulation, we show jets are formed by magnetic reconnection even in the solar photosphere. We also show MHD waves from the jet may affect chromospheric heating and spicule formation. In this talk, I'll introduce our simulation results.	pptx 18MB
	short	K. Nishida	Challenges with Extreme Class-Imbalance and Temporal Coherence: A Study on Solar Flare Data	Azim Ahmadzadeh et al., "Challenges with Extreme Class-Imbalance and Temporal Coherence: A Study on Solar Flare Data", arXiv:1911.09061v1, accepted in IEEE BigData 2019 https://arxiv.org/abs/1911.09061	MB
12-09	main	N.Kimura	Determination of 3D velocity fields of the erupting solar filament on 2016 August 9 using SMART/SDDI at Hida Observatory	Solar flares, explosions on the solar surface, and associated eruptive phenomena affect the interplanetary environment, space weather, and these sometimes cause various damages on our infrastructures. Therefore, it is becoming more and more important to forecast space weather. Filament eruptions, eruptions of cool and plasmas floating in the solar corona into the interplanetary space, highly related to coronal mass ejections, and therefore, they are thought to be one of the sources of magnetic storms. However, the relation among filament eruptions, coronal mass ejections, and magnetic storms has not yet been clarified well. One of the reasons of this is the lack of the accurate measurements of the velocity field of filaments and the temporal evolution. We have not been able to determine precisely whether the plasma is actually ejected into the interplanetary space. It is impossible to obtain the line of sight velocity field of the filament plasma only by H-alpha line center (6562.808 Angstrom) image. The SDDI (Solar Dynamics Doppler Imager) installed in SMART (Solar Magnetic Activity Research Telescope) in Hida observatory can take the solar chromospheric full-disk dataset with 0.25 Angstrom step between -9 to +9 Angstrom centered at H-alpha line. This means that we can get a spectrum of the H-alpha line for the entire region of the filament. In this study, by applying the Becker’s “cloud model” to the filament observation at 73 wavelengths, we could get the line of sight velocity. We calculated the line of sight velocities of the filament eruption which started at 23:30UT on 2016 August 9. The filament is located at the coordinates (x, y) = (-825,319) around the east limb of the sun in the beginning, and the related CME immediately followed the eruption. We tracked the three-dimensional morphological changes of the filament structure entirely from the pre-ejection stage to the disappearance by checking the dense part in H-alpha and AIA images by eyes. We also compared the activities of filament eruption and CME from the aspect of the time variation of the speed and direction to obtain the detailed evolution of the filament eruption which is useful for the space weather forecast.	MB
	short	H. Isobe			MB
12-16	main	H. Tanaka	Estimation of solar ultraviolet irradiance by examining spectroheliogram of Ca II K line	To evaluate the effects of 11-year solar cycle on the Earth’s climate, many studies have been operated as space climate. First thought may come with the total solar irradiance affecting climate change, but it changes only 0.1% in a 11-year activity cycle. Meanwhile, solar ultraviolet (UV) radiation at wavelength ranging 1000-2000A changes more than 10 % over 11 year. Moreover, up to 60% of the total irradiance variations over the solar cycle could be produced at wavelengths below 4000A, and therefore, UV variation could contribute on climate change. Due to the lack of observation with satellites before 1970s, we do not have direct observational data in UVs. On the other hand, the good correlation between solar images in UVs with those in chromospheric lines, such as Ca II K, has been also known. There are astronomical observatories around the world having Ca II K data for a century, at Kyoto University (from 1928) and NAOJ (from 1917) in Japan, Kodaikanal (from 1907) in India, Mt.Wilson (from 1915) in USA, and so on. The bandwidth of the Ca II K line different from observatory to observatory.　By combining these 100-year long Ca II K observations and by investigating the correlation between UV and Ca II K line, we may find a hint on the long-term variation of the solar UV radiation. In this talk we examined correlations between a spectroheliogram of Ca II K line taken by Domeless Solar Telescope (DST) of Hida Observatory, Kyoto University and 304A, 1600A, and 1700A images taken by Atmospheric Imaging Assembly (AIA) on board of Solar Dynamic Observatory (SDO) on May 5, 2018. We found the bandwidths of the Ca II K line which show the highest correlation with 304A, 1600A and 1700A images are 0.04-0.13A, 0.83-1.83A and 1.55-2.38A, respectively. To reproduce shorter wavelength UV, we would be better to use narrow bandwidth of Ca II K line, and to reproduce longer wavelength UV, we would be better to use wider bandwidth of Ca II K line.	pptx 11MB
12-23	main	Y. Tomino	Numerical simulation of magnetic reconnection in partially ionized plasma	In the solar chromosphere, partially ionized plasma exists and many jet phenomena occur.The cause of these phenomena is thought to be sudden energy release by magnetic reconnection.There are many previous studies to understand the structure of shock waves and magnetic fields caused by magnetic reconnection in the solar chromosphere and in these studies partially ionized plasma has been treated as single fluid. However, the validity of the single fluid approximation in the solar chromosphere has not been verified. We are studying the validity of the single fluid approximation by using two-fluid(neutral+plasma) numerical calculations in magnetic reconnection of partially ionized plasma. In my talk, I'll introduce the difference between the results of the single fluid approximation (including ambipolar diffusion) and those of the two-fluid.	pptx 112MB
01-14	D3 presentation	C. Denis
	D3 presentation	A. Tei
01-27	M2 presentation	K. Kihara
	M2 presentation	Y. Kotani
	M2 presentation	D. Yamasaki

Date

Name

Title

Abstract

File

10-01

D3 presentation

H. Hayakawa

10-07

main

Y.W. Huang

short

S. Nagata

10-21

main

T. Sakaue

Disappearance of taller spicules and drastic decrease in wind's mass loss rate in the weak magnetic field

Solar spicule and wind are the manifestations of solar magnetic activity. Their kinetic and thermal features are deeply involved with the magnetic field configuration in the solar atmosphere. Alfvén wave is responsible for the energy transportation in the magnetized atmosphere, and its propagation is affected by some non-linear processes which is crucially important to launch the spicule or drive and heat the solar wind.
To understand the causal relationship between the magnetic field configuration and the resultant features of solar spicule or wind through investigating the non-linear processes of Alfvén wave, we performed the one-dimensional Magneto-Hydrodynamics numerical simulation. In this study, we consider the several magnetic flux tubes with the different field strengths, and investigate the dependence of typical spicule height and solar wind’s mass loss rate on the magnetic field configuration.
The simulation results show the disappearance of taller spicules than 10 Mm and drastic decrease in solar wind's mass loss rate (down to ~ a few x10^{-15} M_\odot yr^{-1}) in the case of weak magnetic field. We will discuss these phenomena is caused by the highly non-linear Alfvén wave in the chromosphere.

pdf
40MB

short

S. Ueno

Which wavelength of solar UV has the strongest influence on the ionosphere?

As one of subjects of the PSTEP project, we are trying to reproduce long-term solar UV variation that has influence on the ionosphere by using full-disk solar chromospheric images. However, we don't know which wavelength of solar UV has the strongest influence on the ionosphere. For this question, different geophysicists give different answers... Therefore, at present, I am investigating actual long-term relationship between one of physical parameter of the ionosphere and solar UV irradiance at various wavelengths. The ionospheric physical parameter that I use is "geomagnetic solar quiet daily variation (Sq)" 1). On the other hand, solar UV irradiance is obtained from several database, such as FISM, DeLand Composite SSI, Ly-alpha Model SSI, and so on 2). I will report present results in this seminar.

References:
1) https://ui.adsabs.harvard.edu/abs/2017SSRv..206..299Y/abstract
2) http://lasp.colorado.edu/lisird/

10-28

main

A. Tei

IRIS Mg II Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole

The solar chromosphere is dynamic and full of fine structures. Among them, spicules are long, thin, dynamic features which jet out ubiquitously from the solar surface, and connect the photosphere to the corona. However, the physical mechanism of spicules and their essential roles related to energy and mass transport is unclear.
We investigated the off-limb spicules observed in the Mg II h and k lines by IRIS in a solar polar coronal hole. We analyzed the large dataset of obtained spectra to extract quantitative information about the line intensities, shifts, and widths. The observed Mg II line profiles are broad and double-peaked at lower altitudes, broad but flat-topped at middle altitudes, and narrow and single-peaked with the largest Doppler shifts at higher altitudes. We use 1D non-LTE (i.e. departures from Local Thermodynamical Equilibrium) vertical slab models in single-slab and multi-slab configurations to interpret the observations and to investigate how a superposition of spicules along the line of sight (LOS) affects the synthetic Mg II line profiles. The used multi-slab models are either static, i. e. without any LOS velocities, or assume randomly assigned LOS velocities of individual slabs, representing the spicule dynamics. We conducted such single-slab and multi-slab modeling for a broad set of model input parameters and showed the dependence of the Mg II line profiles on these parameters. We demonstrated that the observed line widths of the h and k line profiles are strongly affected by the presence of multiple spicules along the LOS. We later showed that the profiles obtained at higher altitudes can be reproduced by single-slab models representing individual spicules. We found that the multi-slab model with a random distribution of the LOS velocities ranging from -25 to 25 km/s can well reproduce the width and the shape of Mg II profiles observed at middle altitudes.

short

A. Asai

•Travel Report : Visit the MUSER site (2019-July-21~24)
•Paper Introduction: Chen, Xingyao, Yan, Yihua; Tan, Baolin; Huang, Jing; Wang, Wei; Chen, Linjie; Zhang, Yin; Tan, Chengming; Liu, Donghao; Masuda, Satoshi, “Quasi-periodic Pulsations before and during a Solar Flare in AR 12242”, 2019, ApJ, 878, id.78

pdf
18MB

11-11

main

K. Kihara

Solar Flare Prediction with Image Recognition, Classification of Sunspot Complexity

A solar flare is an explosive process that releases magnetic energy on the Sun. Solar flares and their accompanied phenomena are crucial problem for space weather, so it is necessary to predict solar flares before their occurrences. Recently, machine learning techniques have been applied to the problem of solar flare prediction. Our group has been studying this using machine learning and image recognition. In order to construct a reliable flare prediction model, we are now carrying out the classification of sunspot complexity. By using the sunspot classification model, it is possible to improve the accuracy of solar flare prediction. In tomorrow's main talk, I will talk about the current status of our work.

pdf
11MB

short

T.T. Ishii

B1.3 flare observed with Sartorius & SMART, on 2019-Nov-05, in NOAA 12750, belongs to Solar Cycle 25.

B1.3 flare observed with Sartorius & SMART,
on 2019-Nov-05, in NOAA 12750,
belongs to Solar Cycle 25.
Report at Zasshikai short, T. T. Ishii
Sartorius at Kwasan, Observer: M. Kamobe
SMART at Hida, Observer: K. Otsuji
Sunspot Sketch 2019/11/01 and report, by A. D. Kawamura

pptx
9.3MB

11-18

main

D. Yamasaki

Polarization Calibration of the Solar Magnetic Activity Research Telescope (SMART)-T4

The Tandem Etalon Magnetograph (TEM) is one of the 4 telescopes of the Solar Magnetic Activity Research Telescope (SMART). TEM is a filter magnetograph, which scans 4 wavelength points around 630.25 nm. TEM aims to obtain vector magnetic fields on the solar photosphere with a spatial resolution of 0.5-1.0 arcsec. A polarimetric sesitivity of 5*10^-4 is achieved for each wavelength point with integrating 675 images in 20 sec (Nagata et al. 2014). In this study, we performed the end-to-end polarization calibration test and evaluated the polarimeter response matrix of TEM in order to suppress any artificial polarization from crosstalk among Stokes vectors under the statistical noise over TEM's field of view(FOV). As a result, we found a significant spatial distribution through TEM's FOV in some components of TEM's response matrix. Then, we investigated a polarizing beam splitter's polarization property and found a circular diattenuation, which may caused by the stress on PBS, with spatial distribution through TEM's FOV. In today's talk, I am going to introduce TEM's polarization observation and the experiments of the calibration.

pdf
17MB

short

K. Otsuji

The Reversal of a Solar Prominence Rotation about Its Ascending Direction during a Failed Eruption

I will briefly introduce the following paper: "The Reversal of a Solar Prominence Rotation about Its Ascending Direction during a Failed Eruption" (https://ui.adsabs.harvard.edu/abs/2018ApJ...864L..37S/abstract), in which a failed filament eruption occurred on 2010 December 10, showing counter-clockwise rotation in the eruptive phase, followed by clockwise motion in the falling phase.

pptx
40MB

11-25

D2 interim report

K. Namekata

恒星の巨大黒点及び恒星スーパーフレアの発生過程の解明に向けた観測的研究

太陽/恒星フレアとは、太陽/恒星表面で起きる突発的な増光現象のことである。近年、太陽型星の長期間観測から、太陽によく似た星では「スーパーフレア」と呼ばれる巨大フレアが起きていることが明らかになり(Maehara et al. 2012)、太陽及び(惑星を持つ)恒星における極端現象が注目されている。私は、恒星スーパーフレアを理解するため、(1)そのトリガーとなる巨大黒点はどのように生成するのか？(2)恒星(スーパー)フレアの放射メカニズムは何か？といった点を明らかにする研究を行なっている。(1)では、恒星黒点の生成・消滅率が、太陽黒点のスケーリング則で説明できることを明らかにした(Namekata et al. 2019, Namekata et al. submitted)。これは、太陽黒点と同様に、磁気浮上により生成し、表面対流によって拡散していく描像を支持する結果である。(2)では、2019年に完成した京都大学岡山3.8mせいめい望遠鏡を用いて、恒星フレアの連続分光・測光観測を行なっている。観測されたスペクトル形状や、波長ごとの放射強度の比の時間変化から、フレアによりエネルギー注入量が変化することや、エネルギー分配がフレアの大小で異なる可能性を発見した。本発表では、これまで博士課程で行なってきた上記の研究の進捗状況と、今後の博士課程における研究の展望を報告する。

12-02

main

Y. Kotani

Numerical simulation of photospheric anemone jets and their influence on the upper atmosphere

Jets phenomenon with a bright loop in their footpoint have been observed in the solar corona and chromosphere and these are called anemone jets.Anemone jets have a spatial scale difference of 10 to 1000 times between the corona and the chromosphere, but they can be explained in a unified way bu magnetic reconnection. From the scale universality of magnetohydrodynamics(MHD), we can expect anemone jets of about 100 km exists even in the solar photosphere. However, it is not obvious whether a jet can be generated by releasing magnetic energy by magnetic reconnection even in the photosphere where magnetic energy is not dominant. In addition, MHD waves generated from photospheric anemone jets may contribute to the chromospheric heating and spicule formation, but no one knows the answer. To answer these questions, we perform 3D MHD simulation including gravity with the solar photospheric parameter. As a result of the simulation, we show jets are formed by magnetic reconnection even in the solar photosphere. We also show MHD waves from the jet may affect chromospheric heating and spicule formation. In this talk, I'll introduce our simulation results.

pptx
18MB

short

K. Nishida

Challenges with Extreme Class-Imbalance and Temporal Coherence: A Study on Solar Flare Data

Azim Ahmadzadeh et al.,
"Challenges with Extreme Class-Imbalance and Temporal Coherence: A Study on Solar Flare Data",
arXiv:1911.09061v1, accepted in IEEE BigData 2019
https://arxiv.org/abs/1911.09061

12-09

main

N.Kimura

Determination of 3D velocity fields of the erupting solar filament on 2016 August 9 using SMART/SDDI at Hida Observatory

Solar flares, explosions on the solar surface, and associated eruptive phenomena affect the interplanetary environment, space weather, and these sometimes cause various damages on our infrastructures. Therefore, it is becoming more and more important to forecast space weather. Filament eruptions, eruptions of cool and plasmas floating in the solar corona into the interplanetary space, highly related to coronal mass ejections, and therefore, they are thought to be one of the sources of magnetic storms. However, the relation among filament eruptions, coronal mass ejections, and magnetic storms has not yet been clarified well. One of the reasons of this is the lack of the accurate measurements of the velocity field of filaments and the temporal evolution. We have not been able to determine precisely whether the plasma is actually ejected into the interplanetary space. It is impossible to obtain the line of sight velocity field of the filament plasma only by H-alpha line center (6562.808 Angstrom) image.
The SDDI (Solar Dynamics Doppler Imager) installed in SMART (Solar Magnetic Activity Research Telescope) in Hida observatory can take the solar chromospheric full-disk dataset with 0.25 Angstrom step between -9 to +9 Angstrom centered at H-alpha line. This means that we can get a spectrum of the H-alpha line for the entire region of the filament. In this study, by applying the Becker’s “cloud model” to the filament observation at 73 wavelengths, we could get the line of sight velocity. We calculated the line of sight velocities of the filament eruption which started at 23:30UT on 2016 August 9. The filament is located at the coordinates (x, y) = (-825,319) around the east limb of the sun in the beginning, and the related CME immediately followed the eruption. We tracked the three-dimensional morphological changes of the filament structure entirely from the pre-ejection stage to the disappearance by checking the dense part in H-alpha and AIA images by eyes. We also compared the activities of filament eruption and CME from the aspect of the time variation of the speed and direction to obtain the detailed evolution of the filament eruption which is useful for the space weather forecast.

short

H. Isobe

12-16

main

H. Tanaka

Estimation of solar ultraviolet irradiance by examining spectroheliogram of Ca II K line

To evaluate the effects of 11-year solar cycle on the Earth’s climate, many studies have been operated as space climate. First thought may come with the total solar irradiance affecting climate change, but it changes only 0.1% in a 11-year activity cycle. Meanwhile, solar ultraviolet (UV) radiation at wavelength ranging 1000-2000A changes more than 10 % over 11 year. Moreover, up to 60% of the total irradiance variations over the solar cycle could be produced at wavelengths below 4000A, and therefore, UV variation could contribute on climate change. Due to the lack of observation with satellites before 1970s, we do not have direct observational data in UVs. On the other hand, the good correlation between solar images in UVs with those in chromospheric lines, such as Ca II K, has been also known. There are astronomical observatories around the world having Ca II K data for a century, at Kyoto University (from 1928) and NAOJ (from 1917) in Japan, Kodaikanal (from 1907) in India, Mt.Wilson (from 1915) in USA, and so on. The bandwidth of the Ca II K line different from observatory to observatory.　By combining these 100-year long Ca II K observations and by investigating the correlation between UV and Ca II K line, we may find a hint on the long-term variation of the solar UV radiation.
In this talk we examined correlations between a spectroheliogram of Ca II K line taken by Domeless Solar Telescope (DST) of Hida Observatory, Kyoto University and 304A, 1600A, and 1700A images taken by Atmospheric Imaging Assembly (AIA) on board of Solar Dynamic Observatory (SDO) on May 5, 2018. We found the bandwidths of the Ca II K line which show the highest correlation with 304A, 1600A and 1700A images are 0.04-0.13A, 0.83-1.83A and 1.55-2.38A, respectively. To reproduce shorter wavelength UV, we would be better to use narrow bandwidth of Ca II K line, and to reproduce longer wavelength UV, we would be better to use wider bandwidth of Ca II K line.

pptx
11MB

12-23

main

Y. Tomino

Numerical simulation of magnetic reconnection in partially ionized plasma

In the solar chromosphere, partially ionized plasma exists and many jet phenomena occur.The cause of these phenomena is thought to be sudden energy release by magnetic reconnection.There are many previous studies to understand the structure of shock waves and magnetic fields caused by magnetic reconnection in the solar chromosphere and in these studies partially ionized plasma has been treated as single fluid. However, the validity of the single fluid approximation in the solar chromosphere has not been verified.
We are studying the validity of the single fluid approximation by using two-fluid(neutral+plasma) numerical calculations in magnetic reconnection of partially ionized plasma. In my talk, I'll introduce the difference between the results of the single fluid approximation (including ambipolar diffusion) and those of the two-fluid.

pptx
112MB

01-14

D3 presentation

C. Denis

D3 presentation

A. Tei

01-27

M2 presentation

K. Kihara

M2 presentation

Y. Kotani

M2 presentation

D. Yamasaki

Date		Name	Title	Abstract	File
04-08	Long	K. Shibata	Solar Physics in future 2019		pdf 35MB
04-15	Long	K. Ichimoto	Solar Projects in 2019		pdf 13MB
04-22	short	K. Namekata	Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometory	I'll introduce the following paper "Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometory". A. F. Lanza, Y. Netto, A. S. Bonomo, H. Parviainen, A. Valio, S. Aigrain https://arxiv.org/abs/1904.04489	pptx 43MB
	main	A. Asai	DKIST		pdf 26MB
05-13	short	A.D. Kawamura			pdf 2.9MB
	main	S. Nagata			pdf 6MB
05-20	short	C. Denis	Mapping the magnetic field of flare coronal loops	in the short talk I am going to introduce the following paper: "Mapping the magnetic field of flare coronal loops", by Kuridze et al. 2019. https://iopscience.iop.org/article/10.3847/1538-4357/ab08e9/meta I will also briefly discuss on the possibility to derive some physical parameters (e.g. temperature, electron density) of the post-flare loop observed by SDDI on 2017 Sep. 10. This based on the theoretical correlations found by Heinzel, Gouttebroze, Vial (1994).	pdf 9.1MB
	main	T.T. Ishii	Introduction of SMART (mainly SDDI) at Hida Observatory, and Recent Solar Activities Observed with SDDI	I would like to talk about introduction of SMART (mainly SDDI) at Hida Obs., and recent solar activities observed with SDDI.	pptx 4.5MB
06-03	short	Y.W. Huang
	main	S. Ueno	40 Years History of Spectroscopic Researches using Domeless Solar Telescope of Hida Observatory (1979 – 2018)	In this year, just 40 years passed after the Domeless Solar Telescope (DST) was built at Hida Observatory in 1979. In this talk, I would like to look back on spectroscopic researches that have been performed in the past 40 years with classifying them by each observation object, as follows. Photosphere (Quiet Region) - Convection - Differential Rotation - Gravitational Redshift - Line Formation Chromospheric Small Activities - Ellerman Bomb & Jet - Grains, Oscillation - Spicule Prominence & Dark Filament - Quiescent Prominence & Filament - Active Prominence & Filament Flare - Kernel (Asymmetry) - Micro-flare - Surge Sunspot & Active Region - Evershed Effect - Emerging Flux	pdf 19MB
06-10	short	K. Kihara	Solar farside magnetograms from deep learning analysis of STEREO/EUVI data	In my short talk, I will introduce the following paper: "Solar farside magnetograms from deep learning analysis of STEREO/EUVI data" Kim, T., Park, E., Lee, H., et al. 2019, Nature Astronomy https://www.nature.com/articles/s41550-019-0711-5	pdf 4.3MB
	main	K. Nishida	The Direct Relation between the Duration of Magnetic Reconnection and the Evolution of GOES Light Curves in Solar Flares	In today's solar seminar, I will talk about following papers: "The Direct Relation between the Duration of Magnetic Reconnection and the Evolution of GOES Light Curves in Solar Flares" Jeffrey W. Reep and Shin Toriumi, 2018, ApJ, 851:4 "Dependence of Durations of Solar Flares on the Size of Inflow Regions", Keisuke Nishida, Naoto Nishizuka, and Shibata Kazunari, in prep	pdf 2.3MB
06-17	M2 interim report	K. Kihara	深層学習による画像認識を用いた太陽フレア予報システムの開発	pdf 3.1MB
	M2 interim report	Y. Kotani	太陽光球で起こるアネモネジェットの数値的研究	pptx 25MB
	M2 interim report	D. Yamasaki	飛騨天文台SMART望遠鏡偏光キャリブレーション	pdf 3.5MB
06-24	short	T. Sakaue		In the tomorrow's seminar, I will shortly introduce the discussion in the following conference: 1. PIPA 2019 6/3 - 6/7 @ Palma de Mallorca (Spain) (http://solar1.uib.es/pipa2019/) 2. TRAPPIST-1 Conference 6/11 - 6/14 @ Liege (Belgium) (https://events.uliege.be/trappist-1/)	pdf 7.0MB
	main	K. Otsuji	Preparing for DKIST: An Introduction to ground based data	In the next solar seminar, I will report the summery of the workshop held at Boulder in three weeks ago. Title: "Preparing for DKIST: An Introduction to ground based data".	pptx 101MB
07-01	short	Y. Kotani	Chromospheric Cannonballs on the Sun	In my short talk, I will introduce the following paper. "Chromospheric Cannonballs on the Sun" Shuhong Yang, Jun Zhang, Xiaohong Li, Zhong Liu, Yongyuan Xiang https://arxiv.org/abs/1906.10850 (ApJL, accepted 2019 June 25)	pdf 4.8MB
	main	H. Isobe	IRIS/SDDI observation of an emerging flux region	I will be talking about “IRIS/SDDI observation of an emerging flux region” on which I have been working with Durgesh Tripathi and his student, also with a help from Otsuji-san about the SDDI data.	pptx 34MB
07-08	short	A. Tei	Spectral Diagnosis of Mg II and Hα Lines during the Initial Stage of an M6.5 Solar Flare	In the tomorrow's short talk, I will introduce Huang et al. 2019, ApJL, 878, 15.The title is "Spectral Diagnosis of Mg II and Hα Lines during the Initial Stage of an M6.5 Solar Flare". https://ui.adsabs.harvard.edu/abs/2019ApJ...878L..15H/abstract	MB
	main	A.D. Kawamura			MB
07-22	short	D. Yamasaki	Very Fast Helicity Injection Leading to Critically Stable State and Large Eruptive Activity in Solar Active Region NOAA 12673	In my tomorrow’s solar seminar short talk, I will introduce “Very Fast Helicity Injection Leading to Critically Stable State and Large Eruptive Activity in Solar Active Region NOAA 12673” (Vemareddy 2019):https://ui.adsabs.harvard.edu/abs/2019ApJ...872..182V/abstract	pdf 17MB
	main	C. Denis	Fast-filament eruption detected by SMART/SDDI on 2017 April 23	Tomorrow in main talk of the solar seminar, I will present progress about my analysis of the "fast-filament eruption detected by SMART/SDDI on 2017 April 23". In the first part of my presentation I am going to discuss the kinematics, while in the second part I will show a very rough estimation of the kinetic and potential energies of the filament eruption.	pdf 8.8MB
07-29	No seminar

Date

Name

Title

Abstract

File

04-08

Long

K. Shibata

Solar Physics in future 2019

pdf
35MB

04-15

Long

K. Ichimoto

Solar Projects in 2019

pdf
13MB

04-22

short

K. Namekata

Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometory

I'll introduce the following paper "Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometory". A. F. Lanza, Y. Netto, A. S. Bonomo, H. Parviainen, A. Valio, S. Aigrain https://arxiv.org/abs/1904.04489

pptx
43MB

main

A. Asai

DKIST

pdf
26MB

05-13

short

A.D. Kawamura

pdf
2.9MB

main

S. Nagata

pdf
6MB

05-20

short

C. Denis

Mapping the magnetic field of flare coronal loops

in the short talk I am going to introduce the following paper: "Mapping the magnetic field of flare coronal loops", by Kuridze et al. 2019. https://iopscience.iop.org/article/10.3847/1538-4357/ab08e9/meta I will also briefly discuss on the possibility to derive some physical parameters (e.g. temperature, electron density) of the post-flare loop observed by SDDI on 2017 Sep. 10. This based on the theoretical correlations found by Heinzel, Gouttebroze, Vial (1994).

pdf
9.1MB

main

T.T. Ishii

Introduction of SMART (mainly SDDI) at Hida Observatory, and Recent Solar Activities Observed with SDDI

I would like to talk about introduction of SMART (mainly SDDI) at Hida Obs., and recent solar activities observed with SDDI.

pptx
4.5MB

06-03

short

Y.W. Huang

main

S. Ueno

40 Years History of Spectroscopic Researches using Domeless Solar Telescope of Hida Observatory (1979 – 2018)

In this year, just 40 years passed after the Domeless Solar Telescope (DST) was built at Hida Observatory in 1979. In this talk, I would like to look back on spectroscopic researches that have been performed in the past 40 years with classifying them by each observation object, as follows.

Photosphere (Quiet Region)
- Convection
- Differential Rotation
- Gravitational Redshift
- Line Formation
Chromospheric Small Activities
- Ellerman Bomb & Jet
- Grains, Oscillation
- Spicule
Prominence & Dark Filament
- Quiescent Prominence & Filament
- Active Prominence & Filament
Flare
- Kernel (Asymmetry)
- Micro-flare
- Surge
Sunspot & Active Region
- Evershed Effect
- Emerging Flux

pdf
19MB

06-10

short

K. Kihara

Solar farside magnetograms from deep learning analysis of STEREO/EUVI data

In my short talk, I will introduce the following paper:
"Solar farside magnetograms from deep learning analysis of STEREO/EUVI data" Kim, T., Park, E., Lee, H., et al. 2019, Nature Astronomy
https://www.nature.com/articles/s41550-019-0711-5

pdf
4.3MB

main

K. Nishida

The Direct Relation between the Duration of Magnetic Reconnection and the Evolution of GOES Light Curves in Solar Flares

In today's solar seminar, I will talk about following papers:
"The Direct Relation between the Duration of Magnetic Reconnection and the Evolution of GOES Light Curves in Solar Flares" Jeffrey W. Reep and Shin Toriumi, 2018, ApJ, 851:4

"Dependence of Durations of Solar Flares on the Size of Inflow Regions", Keisuke Nishida, Naoto Nishizuka, and Shibata Kazunari, in prep

pdf
2.3MB

06-17

M2 interim report

K. Kihara

深層学習による画像認識を用いた太陽フレア予報システムの開発

pdf
3.1MB

M2 interim report

Y. Kotani

太陽光球で起こるアネモネジェットの数値的研究

pptx
25MB

M2 interim report

D. Yamasaki

飛騨天文台SMART望遠鏡偏光キャリブレーション

pdf
3.5MB

06-24

short

T. Sakaue

In the tomorrow's seminar, I will shortly introduce the discussion in the following conference:
1. PIPA 2019 6/3 - 6/7 @ Palma de Mallorca (Spain) (http://solar1.uib.es/pipa2019/)
2. TRAPPIST-1 Conference 6/11 - 6/14 @ Liege (Belgium) (https://events.uliege.be/trappist-1/)

pdf
7.0MB

main

K. Otsuji

Preparing for DKIST: An Introduction to ground based data

In the next solar seminar, I will report the summery of the workshop held at Boulder in three weeks ago.
Title: "Preparing for DKIST: An Introduction to ground based data".

pptx
101MB

07-01

short

Y. Kotani

Chromospheric Cannonballs on the Sun

In my short talk, I will introduce the following paper.
"Chromospheric Cannonballs on the Sun"
Shuhong Yang, Jun Zhang, Xiaohong Li, Zhong Liu, Yongyuan Xiang
https://arxiv.org/abs/1906.10850
(ApJL, accepted 2019 June 25)

pdf
4.8MB

main

H. Isobe

IRIS/SDDI observation of an emerging flux region

I will be talking about
“IRIS/SDDI observation of an emerging flux region”
on which I have been working with Durgesh Tripathi and his student, also with a help from Otsuji-san about the SDDI data.

pptx
34MB

07-08

short

A. Tei

Spectral Diagnosis of Mg II and Hα Lines during the Initial Stage of an M6.5 Solar Flare

In the tomorrow's short talk, I will introduce Huang et al. 2019, ApJL, 878, 15.The title is "Spectral Diagnosis of Mg II and Hα Lines during the Initial Stage of an M6.5 Solar Flare".
https://ui.adsabs.harvard.edu/abs/2019ApJ...878L..15H/abstract

main

A.D. Kawamura

07-22

short

D. Yamasaki

Very Fast Helicity Injection Leading to Critically Stable State and Large Eruptive Activity in Solar Active Region NOAA 12673

In my tomorrow’s solar seminar short talk, I will introduce “Very Fast Helicity Injection Leading to Critically Stable State and Large Eruptive Activity in Solar Active Region NOAA 12673” (Vemareddy 2019):https://ui.adsabs.harvard.edu/abs/2019ApJ...872..182V/abstract

pdf
17MB

main

C. Denis

Fast-filament eruption detected by SMART/SDDI on 2017 April 23

Tomorrow in main talk of the solar seminar, I will present progress about my analysis of the "fast-filament eruption detected by SMART/SDDI on 2017 April 23".
In the first part of my presentation I am going to discuss the kinematics, while in the second part I will show a very rough estimation of the kinetic and potential energies of the filament eruption.

pdf
8.8MB

07-29

No seminar