Self-similar Reconnection: A new model
for astrophysical application beyond the Petschek model
Shin-ya Nitta
I present a new model for time evolution of the fast
magnetic reconnection in a free space, which is
specialized for astrophysical applications and is
characterized by self-similarity. The possibility of this
type of evolution is verified by numerical simulations. We
also find an analytical solution which is consistent with
the numerical result. The reconnection rate of this model
is spontaneously determined by the reconnection system
itself through the process to form the outflow
structure.In many cases of astrophysical problems, e.g.,
solar flares or geomagnetospheric substorms, the spatial
scale of the reconnection system significantly expands as
time proceeds. The resultant spatial scale of the
reconnection system is much larger than the initial scale
(its dynamic range is typically 7 orders of magnitude).
Such evolution should be treated as a spontaneous
evolution in a free space. In spite of this, most previous
works focused on the character of evolution strongly
affected by artificial boundary conditions (so-called
"driven reconnection"). The focus of this work is on this
spontaneous expanding phase. Our theoretical contribution
is to establish a new model for magnetic reconnection and
to clarify a realistic evolution and spontaneous structure
formation in the free space.
Correspondence
Shin-ya Nitta, The Graduate University for Advanced Studies
presentation
poster