Cause of super-thermal electron heating during magnetotail reconnection

Abstract

We present a candidate mechanism for the energization of super-thermal electrons during magnetic reconnection in the Earth's magnetotail. By analyzing in-situ measurements of electron distribution functions we characterize the relative energy gain of the electrons as a function of energy, ΔEΔ(E). For all the events considered the high energy part of ΔE(ΔE) is nearly independent of E. This is the signature of energization in an acceleration potential,φ||, which is caused by parallel electric fields in the vicinity of the reconnection region. The same acceleration mechanism is also documented for a kinetic simulation of reconnection. Copyright © 2010 by the American Geophysical Union.