Plasma Physics Seminar ( Phys 769)

Dr. Michael Hesse,  NASA

Anti-parallel and Component Magnetic Reconnection: A Comparison

Magnetic reconnection operates in two regimes. In the first, nearly
anti-parallel magnetic fields reconnect, whereas the second mode involves
significant "guide" magnetic fields, directed along the main current flow
in the inner dissipation region. Physically, these two regimes can be
distinguished by analyses on ion and electron orbital behavior within their
respective demagnetization regions. For either species, reconnection is
effectively anti-parallel, if the particle Larmor radius, in the guide
field, within the diffusion region exceeds the dimensions of the latter. In
case the Larmor radius exceeds the diffusion region dimensions, the
particle bounce motion in the poloidal field reversal is inhibited and a
different mechanism has to effect particle demagnetization. In this latter
case, reconnection is best described as component reconnection. Both cases
are deemed to be applicable in space plasmas, ranging from anti-parallel
reconnection in the nightside magnetosphere to reconnection of highly
sheared magnetic fields in the solar corona. We will use high-resolution
particle-in-cell simulations to compare properties of the two regimes. In
particular, we will focus on particle properties, and the demagnetization
processes acting in the case of component reconnection.