  For the nonthermal radio emission of the Galactic Center Arc in situ electron
acceleration is imperative. The observed radio spectrum can be modeled by a
transport equation for the relativistic electrons which includes particle
acceleration by electric fields, momentum diffusion via scattering by
magnetohydrodynamical turbulence and energy losses by synchrotron radiation.
The accelerating electric fields can be regarded as a natural consequence of
multiple reconnection events, caused by the interaction between a molecular
cloud and the Arc region. The radio spectrum and even the recently detected 150
GHz emission, explicitely originating from the interaction regions of a
molecular cloud with the magnetized Arc, can be explained in terms of
quasi-monoenergetically distributed relativistic electrons with a typical
energy of about 10 GeV accelerated in stochastically distributed magnetic
reconnection zones.

Astrophysics