Electrodynamics at Galactic Center

Abstract

Molecular clouds moving at Keplerian velocities can induce strong electric fields in ionized regions near the galactic center. The induced field can drive currents over equivalent circuits ~ 100 pc. along the highly ordered magnetic fields, B ~ 10⁻³G. Such current paths drive low-level ion acoustic turbulence, providing a resistance in the circuit. Small magnetic pinches form which are generally kink unstable, but can organize into larger, long-lived structures. Ohmic losses are energetically important in the molecular clouds, where high density regions should be most luminous. Electrons can accelerate in the induced fields to relativistic energies, yielding the radio luminosity. Electrodynamic flares may occur on year timescales. Such electrodynamic deceleration of clouds can powerfully increase accretion toward galactic centers and enhance their luminosities.