Speaker
Mr
fabien widmer
(Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany)
Description
Magnetic reconnection is a very efficient process to convert magnetic
energy into
kinetic plasma energy. Unfortunately, models of reconnection such as
Sweet Parker, do
not agree with the time scale observed during the impulsive phase of a
Solar flares,
providing only small reconnection rates. One possible approach for
reaching fast
reconnection observed is by considering small scales effects of
magnetic field and
plasma turbulence. To catch small scale effects, sub-grid scales models
of turbulence
are considered in MHD numerical simulation of global scale eruption.
Different
sub-grid models, a nonlinear model of turbulence (Grete & al. 2015)
and a
Reynolds-Average Navier-Stokes (RANS) (Yokoi 2013) are tested on a
double current
sheet, where their associated reconnection rates are computed and
compared with those
of the usual resistive MHD. It shows that turbulence can increase the
reconnection
rate in a significant way. Finally, high resolution simulation of cascading
reconnection is used to directly compute small scales quantities in
order to test the
validity of the RANS turbulent model
Primary author
Mr
fabien widmer
(Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany)
Co-authors
Prof.
Jörg Büchner
(Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany)
Prof.
Nobumitsu Yokoi
(Institute of Industrial Science, University of Tokyo, Tokyo, Japan)
