Frictionally heated electrons in the high-latitudeDregion

Abstract

[1] A semiempirical, physical model of electron momentum and energy in the D region is developed to investigate natural mechanisms for enhancing D region electron temperatures. The modeled D region electron temperatures are enhanced in the presence of strong magnetospherically mapped electric fields and are independent of the D region electron density. Results indicate that electric field strengths exceeding 50 mV/m cause significant frictional heating of the D region electron gas. Balanced by elastic and inelastic collisions with neutrals, frictional heating can heat the D region electron gas up to 3 times the neutral temperature. Sondrestrom incoherent scatter radar (ISR) measurements during the Halloween storm of October 2003 observed an anticorrelation between the locally observed electric field strength and the measured D region backscattered power. It is found through modeling that D region electron temperatures are enhanced during the time of the observed decrease in backscattered power. The electron temperature dependency in the ISR total cross section accounts for the decrease in backscattered power. The natural increase in D region electron temperatures due to strong magnetospheric electric fields can have implications on polar D region chemistry, conductivity, and plasma diffusion.