Speaker
Prof.
Igor Rogachevskii
(Ben-Gurion University of the Negev and Nordita)
Description
We study different regimes of magnetic reconnection during formation
of bipolar structures using direct numerical simulations of the equations
of magnetohydrodynamics
with external random forcing and in the presence of gravity.
The domain is divided into two parts: a lower layer with the helical
forcing
and an upper layer with the non-helical forcing
with a smooth transition in between.
At early times, a large-scale helical dynamo develops in the bottom
layer,
and at later times the dynamo saturates, but the vertical magnetic field
continues to develop and rises to form dynamic
bipolar structures at the top. Later, the magnetic reconnection
of the bipolar structures causes their evolution and destruction, and
new bipolar structures
form in other place, etc.
This is the first example of magnetic flux concentrations, owing
to strong density stratification, from
self-consistent dynamo simulations that generate bipolar,
super-equipartition strength, magnetic structures whose energy density
can exceeds the turbulent kinetic energy by even a factor of ten.
Primary author
Prof.
Igor Rogachevskii
(Ben-Gurion University of the Negev and Nordita)
Co-authors
Axel Brandenburg
(Nordita)
Dr
Dhrubaditya Mitra
(Nordita)
Nathan Kleeorin
(Ben-Gurion University of the Negev and Nordita)
Mrs
Sarah Jabbari
(Nordita)
