| Date | Name | Title | Abstract | File |
| Date | Name | Title | Abstract |
| Date | Name | Title | Abstract | File | |
| 4/13 | Announcement | Y. Notsu | Introduction of Solar Seminar | ||
| K. Ichimoto | Solar-Cと太陽圏観測ネットワークと飛騨 | ||||
| 4/20 | K. Shibata | ・Space Weather Workshop 報告 ・太陽研究の今後の重要課題：われわれは何をすべきか？ |
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| 4/27 | Short | H. Tamazawa |
"Solar activity around AD 775 from aurorae and radiocarbon" R.Neuhauser and D. L. Neuhauser doi:10.1002/asna.201412160 arXiv:1503.01581 "Cosmic ray event of A.D. 774-775 shown in quasi-annual 10Be data from the Antarctic Dome Fuji ice core" Miyake, F., et al. 2015 GeoRL 42 84 ADS |
pptx | |
| Main | S. Ueno |
明日の太陽雑誌会では、改めて以下の内容について、
日本語で紹介させて頂きたいと思います。
（資料自体は概ね英語になる予定です。）
１．飛騨ドームレス太陽望遠鏡とスペクトロヘリオグラフの紹介と、 上野が解析しかけている現象（Ellerman Bombと彩層グレイン）についての紹介。 ２．ＣＨＡＩＮプロジェクトの紹介と、上野も含め、今まで複数の人々が 解析してきたが、まだまとめきれていない研究課題数点（フィラメント噴出とＣＭＥとの関係、フィラメント噴出と衝撃波・モートン波との関係、 彩層全面画像による紫外線放射量変動の再現）についての紹介。 |
ppt | 5/11 | Short | S. Takasao |
As today's short talk, I will introduce two papers on infalling plasma blobs, which focus on the fundamental processes of mass accretion. Reale et al. 2013 Science http://adsabs.harvard.edu/abs/2013Sci...341..251R Reale et al. 2014 ApJ http://adsabs.harvard.edu/abs/2014ApJ...797L...5R |
pptx |
| Main | S. Nagata |
I am going to briefly introduce the Solar-C mission proposal and science
goals as one of the Solar-C working group members.
We would like to discuss with all of you how to achieve those goals, focusing on flares and reconnection study. We welcome your any critical comments. |
-- | ||
| 5/18 | Short | N. Nakamura | Emerging flux in partially ionized atmosphere | Today, I will review the paper below,
which study the effect of partially ionized plasma
in emerging flux process.
http://adsabs.harvard.edu/abs/2013ApJ...764...54L |
pptx |
| Main | T. T. Ishii | White light flares observed with SMART/FISCH | Tomorrow, I would like to talk about
'White light flares observed with SMART/FISCH',
especially about the flare on 2015-May-06(JST).
|
pptx | |
| 5/25 | Short +α | A. D. Kawamura | On the next meeting, I will introduce an IBEX paper McComas + (2014), IBEX: First Five Years (2009-2013) http://adsabs.harvard.edu//abs/2014ApJS..213...20M with a brief review of recent Heliophysics with IBEX and Voyagers. |
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| -- | Data review | Anan-san showed the following paper. http://adsabs.harvard.edu/abs/2012ApJ...750L..25J |
-- | ||
| 6/1 | M2 Practice | Y. Notsu | スーパーフレアを起こした太陽型星の 高分散分光観測 | ||
| 6/1 | M2 Practice | T. Hiraishi | スーパーフレアがおよぼす地球磁気圏への影響 | -- | |
| 6/8 | Short | T. Takahashi | "Three dimensional MHD Modeling of Vertical Kink Oscillations in an Active Region Plasma Curtain" | In the short talk today, I will introduce a paper titled
"Three dimensional MHD Modeling of Vertical Kink Oscillations in an Active Region Plasma Curtain"
by Ofman, L. submitted to arXiv last month. http://arxiv.org/pdf/1505.05427v1.pdf This topic is related to the main talk by Nishida-san today. |
pptx |
| Main | K. Nishida | Today, I will talk about "Prominence oscillations triggered by MHD wave".
based on my talk in the ASJ autumn meeting 2012. http://www.asj.or.jp/nenkai/2012b/html/M40a.html |
pptx | ||
| 6/15 | Short | S. Takeshige | "Magnetic reconnection and stochastic plasmoid chains in high-Lundquist-number plamsmas" | I will introduce the paper,
"Magnetic reconnection and stochastic plasmoid chains in high-Lundquist-number plamsmas", Loureiro et al. 2012. http://adsabs.harvard.edu/abs/2012PhPl...19d2303L |
pptx |
| Main | H. Isobe | "Dynamical formation and thinning of current sheet" | I will talk about my own work on
"Dynamical formation and thinning of current sheet"
Here's a movie from my presentation (which is not ready yet) http://www.kwasan.kyoto-u.ac.jp/~isobe/tmp/e0.003dx0.001.gif |
pptx | |
| 6/22 | Short | Y. Notsu | "Some topics on chromospheric activity of solar-type stars and the Sun in this several decades (Before the era of Kepler space telescope)." |
In my short talk tomorrow,
I introduce some topics on chromospheric activity of solar-type stars
and the Sun in this several decades (before the era of Kepler space telescope).
Reference: Hall (2008) Liv Rev. Sol Phys, 5, 2 “Stellar Choromospheric Activity” http://adsabs.harvard.edu/abs/2008LRSP....5....2H Giampapa (2005) “Stellar analogs of solar activity: the Sun in a stellar context” http://link.springer.com/chapter/10.1007%2F3-540-27510-X_3 Livingston (2007) ApJ, 657, 1137 “Sun-as-a-Star Spectrum Variations 1974-2006” http://adsabs.harvard.edu/abs/2007ApJ...657.1137L |
|
| Main | T. Anan | "Decoupling of neutral atoms from plasma in a solar prominence" | In many astrophysical systems the low temperature of the plasma means that it is only partially ionized. In these systems, the motion of ions is frozen to that of the magnetic field, but neutral particles can only feel the magnetic field’s Lorentz force indirectly through collisions with ions. This drift in the velocity between ionized and neutral species plays a key role in modifying important physical processes like magnetic reconnection, damping of magneto- hydrodynamic waves, transport of angular momenta in the formation and evolution of stars and disks, and heating in the solar chromosphere. However, observations that detail the properties of the ion-neutral drift are lacking. Here we report observations of the decoupling of neutral atoms from calcium ions, and by extension the magnetic field, in a solar prominence as shown by the difference in their Doppler-velocities. We simultaneously observed spectra of the prominence in Hε (H I 397 nm) and Ca II (397 nm) using a high dispersion spectrograph of the Domeless Solar Telescope at Hida observatory, finding differences in Doppler-velocity of neutral atoms and calcium ions to be on almost three orders of magnitude larger than those theoretically predicted. Simulations of instabilities in prominences have shown that high drift velocity can be locally formed as the system evolves (Khomenko et al. 2014), here we present the first observational signature of such kind of high drift velocity. | pptx | |
| 6/29 | D2 Presentation (13:00-14:00) |
A. D. Kawamura | "An inspection of a steady current sheet of a partially ionized plasma in local thermal equilibrium" | ||
| 7/6 | Short | M. Sano | "Spectro-Polarimetric Imaging Reveals Helical Magnetic Fields In Solar Prominence Feet" |
I will introduce the paper,
"Spectro-Polarimetric Imaging Reveals Helical Magnetic Fields In Solar Prominence Feet",
M. J. Mratinez Gonzales et al. 2015. http://iopscience.iop.org/0004-637X/802/1/3/pdf/apj_802_1_3.pdf |
|
| Main | N. Nakamura | "Partially Ionized Plasma Effect in Dynamic Solar Atmosphere" | The title of my talk today is "Partially Ionized Plasma Effect inDynamic Solar Atmosphere" which is a talk about partially ionized effect in solar atmosphere. | pptx | |
| 7/13 | Short | K. Hirose |
I will introduce the paper, "Direct spatial association of an X-ray flare with the eruption of a solar quiescent filament", Gordon D. Holman and Adi Foord, 2015. http://adsabs.harvard.edu/abs/2015ApJ...804..108H |
pptx | |
| Main | S. Takasao | "numerical study on the formation of delta-spot regions" |
I will introduce my numerical study on the formation of delta-spot regions, where delta-spot regions are known to be the most flare-productive active regions.
The abstract is as follows: We for the first time carried out MHD simulations where a subsurface twisted kink-unstable flux tube emerges from the solar interior to the corona. Unlike the previous expectations based on the bodily emergence of a kinked tube, we found that the kinked tube can naturally form a complex quadrupole structure at the photosphere. Due to the development of the kink instability and a strong horizontal expansion before the emergence, the magnetic shear at the kinked apex of the tube is greatly reduced, although the other parts of the tube is still strongly twisted. This leads to the formation of a complex quadrupole structure: a pair of the coherent spots with a strong twist and a narrow complex polarity pair between it. The quadrupole is formed by the submergence of a portion of emerged magnetic fields. This study could be important for understanding of the origin of complex multipolar delta-spot regions that have a strong magnetic shear and emerge with polarity orientations not following Hale-Nicholson and Joy Laws. |
pptx | |
(14:00-16:00) |
at 3rd floor lecture room (328) |
K. Takizawa | "太陽活動第23期におけるδ型黒点の生成発展とフレア活動" | pptx | |
(13:00-) |
-- | ||||
| I will introduce my study on the effect of coronal temperature on the formation process of solar chromospheric jets using two-dimensional radiative magnetohydrodynamic simulations from the upper convection zone to the lower corona. The numerical code includes the effect of a LTE equation of state, optically thick radiative loss in the photosphere, optically thin radiative loss in the chromosphere and the corona, and thermal conduction along the magnetic field lines. Many chromospheric jets are produced in the simulations by shock waves passing through the transition region. We find a clear dependence of the scale of these simulated on the coronal temperature, taller when the coronal temperature is lower and shorter when the coronal temperature is higher. The statistical property on the scale of chromospheric jets are compared with the results by Shibata & Suematsu (1982). We also show how the deceleration of simulated jets is affected by the coronal temperature. | -- | ||||
|
During the impulsive phase of solar flares, many signs of rapid heating,
flows and/or turbulence have been found in high temperature emission
lines in a flaring loop. These phenomena have been suggested as evidence
of magnetic reconnection and are related to particle acceleration. Rapid
heating will lead to non-equilibrium ionization and a non-Maxwellian
electron energy distribution. The temporal and spatial evolution of this
non-Maxwellian distribution in a flare loop may demonstrate the process
of heating by magnetic reconnection, and particle acceleration.
Coronal EUV lines are mainly excited by electron collision, so that their intensities have information of the electron distribution. In this presentation, we review the emission process of coronal EUV lines and discuss the particle diagnosis as well as the plasma diagnosis with Hinode/EIS observations. |
pptx | ||||
|
I'll introduce the following paper;
D.R. Graham and G. Cauzzi, 2015, ApJL, 807, L22 Temporal Evolution of Multiple Evaporating Ribbon Sources in a Solar Flare http://ads.nao.ac.jp/abs/2015ApJ...807L..22G In this paper, an X-class flare was observed by IRIS with a lot of spectra on the flare kernels. Mainly, the chromospheric evaporation and chromospheric condensation are reported and discussed. |
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| In today's seminar, I will introduce our research project,
interdisciplinary research of extreme space weather, space climate and
aurora,
"Aurora4D project : Past, Present and Future of Aurora and Our Society"
In our project, we survey and compile the sunspots and aurora records in historical documents from various locations and languages, ultimately providing it to the academic community, not only community of natural science but also human and social sciences, as open data. In our previous research, we present the results of a comprehensive survey of sunspots and aurora records in Chinese formal chronicles spanning the 6th to 13th. |
pptx | ||||
|
I will introduce the following paper;
Title: Simulations of Solar Jets Confined by Coronal Loops Authors: Wyper, P. F.; DeVore, C. R. Publication: eprint arXiv:1509.07901 (submitted to ApJ) http://adsabs.harvard.edu/abs/2015arXiv150907901W http://arxiv.org/abs/1509.07901 In this paper, they explore the application of the embedded-bipole model to jets occurring in closed coronal loops, and find that the jet characteristics are highly sensitive to the ratio of the footpoint separation of the coronal loop to the width of the jet source region. |
-- | ||||
| -- | |||||
| Today I will introduce the following paper
Title: Fast-to-Alfven Mode Conversion Mediated by Hall Current. I. Cold Plasma Model Authors: Paul S. Cally, Elena Khomenko Links: http://arxiv.org/abs/1510.03927 |
-- | ||||
| pdf |
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|
"Dichotomy of Solar Coronal Jets:Standard Jets and Blowout Jets" Moore et al.(2010 APJ 720 757) "Fibrillar Chromospheric Spicule-Like Counterparts to an Extreme-Ultraviolet and Soft X-ray Blowout Coronal Jet" Sterling et al. (2010 APJ 722 1644) |
pptx | ||||
| I will introduce the preliminary result of our literature survey project for long term solar activity, now as a part of Aurora4D project. This results is treated as a chronological extension of Hayakawa + (2015), with a bit of different sense. The target era Qing Dynasty (1616-1911) is geological and chronological crossroad of scientific western and traditional eastern wisdom. Therefore, unlike other Chinese dynasty, the records from Qing dynasty can be verified with more scientific data. | -- | ||||
|
We have studied superflares on solar-type stars by using Kepler
photometric data and Subaru spectroscopic data.
In the first half of this presentation, I show the recent results
of our superflare studies. In particular, I focus on flares found from
Kepler short (1-min) cadence data (Maehara+2015 EPS), and the comparison
of superflares on G, K, M stars.
In the latter half, I introduce our future research plans using Kyoto-Okayama 3.8m new telescope and its new spectrograph. I also briefly mention the future space mission (TESS and PLATO) after Kepler. |
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| Plasma environment around the Earth is continuously driven by varying solar wind. It is generally called “space weather”. The biggest drivers of space weather disturbances are coronal mass ejections (CMEs) which are bulk of plasma launched from the solar corona during solar flares. Magnetic flux transported by CMEs through interplanetary space sometimes reach the Earth and interact with Earth' dipole magnetic field resulting in huge magnetic storms. Interplanetary shock waves associated with fast CMEs accelerate protons and often make the radiation level in space rise suddenly. In my talk, we will focus on several questions related to basic properties of CMEs and basic dynamical processes during magnetic energy release, such as how fast can CMEs become in extremely large flare events, how strong flare-associated shock waves are near the Sun, how impulsive and intermitted nature of magnetic reconnection is realized during solar flares and so on, from the view point of magnetohydrodynamics(MHD). If we have time, we want to introduce a new MHD code “NOODLES” and discuss its advantage and disadvantages. | |||||
| -- | |||||
| Spicules are high-speed, cool jets observed ubiquitously on the solar surface, but their origin remains unclear. Recent observations reported that more than 50% of spicules may have a double-thread structure. It is speculated that magnetic reconnection between flux tubes tangled by the photospheric plasma motions can result in the formation of a pair of spicules along the pair of the reconnected fields, but no theoretical investigation has been done yet. Considering a reconnected field geometry, we developed a simplified spicule model considering a reconnected field geometry. Using this, we carried out 1.5D MHD simulations to understand the generation of spicules by reconnection. We found that an upward-propagating intermediate shock as well as a slow shock are generated when a reconnected field line relaxes. Both of them eventually accelerate the plasma in the upper chromosphere, launching spicules. The dependence of the spicule height on physical quantities is also investigated to compare this model with other spicule models. We give a theoretical explanation to the dependence. This study is relevant for understanding the relation between spicules and unresolved reconnection at their foot points. | pptx | ||||
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@ Room 511 of Building 5 |
"Space Weather Forecasting for Solar Flares" | Solar flares are one part of the very complicated Heliospheric Space
Weather system. In addition to their own immediate impacts, Flares are
(sometimes) associated with Coronal Mass Ejections and Solar Energetic
Particles. In this seminar, I will discuss Space Weather forecasting
with a focus on Solar Flares, including their impact on the Earth
and Heliosphere, and the need for true forecasting (as compared to
"now-casting") methods for these statistically rare events. I will
ask "How well are forecasts doing?", discuss how success is measured,
and finally ask "what is needed next?" in order to improve future Solar
Flare forecasts. http://www.usss.kyoto-u.ac.jp/seminar.html We also have informal seminar with K. D. Leka-san at the same date. Time: 13:00-15:30, Place: 3rd floor seminar room |
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13:30 - 15:30 @ 3rd floor seminar room |
thesis presentation (MHD Seminar) |
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| The Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO) spacecraft has observed more than 24,000 coronal mass ejections (CMEs) from 1996. We report on statistical properties of CMEs with particular emphasis on a comparison of solar cycles 23 and 24. It is known that the average sunspot number (SSN) has declined by ~40% but CME occurrence rate did not drop in cycle 24 unlike SSN. Because approximately 40% of the CMEs originate from non-sunspot regions, it is not necessary for the CME rate to follow SSN perfectly. In fact, the number of prominence eruptions, which is closely related to the CMEs, observed by Nobeyama radio heliograph did not drop. The number of magnetic clouds (MCs), which is the interplanetary counterpart of the CMEs, did not decline in cycle 24. The statistical behavior of CMEs and their geoeffectiveness will be discussed. | |||||
(11:00 - 12:00) @ 1th floor meeting room (127) |
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(10:00 - 17:00) @ 5th floor meeting room |
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(16:00 - 18:00) @ 5th floor meeting room |
& H. Kee (Magara-san's student) |
Solar magnetic fields produce various dynamic phenomena such as solar flares and coronal mass ejections, and numerical simulations have been a powerful tool to clarify dynamic processes involved in these phenomena. In this talk I report recent research activities of our group. The topics are:
• NLFF modeling of the flare producing active region 12158 • Solar eruption model coupled with solar winds <--------- Lee Hwanhee's partt • Global MHD simulation of an ICME We show several key results from our MHD simulations performed for investigating these topics. We then discuss what have been resolved through these simulations and what are remaining issues that should be clarified in future research. |
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11:00-12:00 @5th floor meeting room |
thesis presentation |
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15:00- |
thesis presentation (MHD Seminar) |
& Y. Notsu & T. Hiraishi |
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I will talk about CLASP1&2 science meeting in this week, and introduce of a paper. |
The paper is Tlatov et al. Tilt Angles of Solar Filaments over the Period 1919-2014 http://adsabs.harvard.edu/abs/2016arXiv160102342T or Wedemeyer-Bohm and Carlsson 2011 Non-equilibrium calcium ionization in the solar atmosphere http://adsabs.harvard.edu/abs/2011A%26A...528A...1W or …. pptx |
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Concerning the "short talk",
I would like to introduce the following paper today:
"A Different View of Solar Spectral Irradiance Variations: Modeling Total Energy over Six-Month Intervals" by Thomas N. Woods et al. (2015, Solar Phys., DOI 10.1007/s11207-015-0766-0) http://adsabs.harvard.edu/abs/2015SoPh..290.2649W being conscious of relation with A04 Group "Solar Cycle Activity and Impact on Climate" under "Project for Solar-Terrestrial Environment Prediction (PSTEP)". |
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