The Alfven-Falthammar formula for the parallel E-field and its analogue in downward auroral-current regions

Author

Jasperse, John R. ; Grossbard, Neil J.

Author_Institution

Air Force Res. Lab., Hanscom AFB, MA, USA

Volume

28

Issue

6

fYear

2000

fDate

12/1/2000 12:00:00 AM

Firstpage

1874

Lastpage

1886

Abstract

The authors give an alternative derivation of the Alfven-Falthammar formula for a positive parallel E-field in upward auroral-current regions and its analogue for a negative parallel E-field in downward auroral-current regions. These formulas give new insight into the physics of the Birkeland current system. They find that for downward auroral-current regions, the velocity-space anisotropy in the ion distribution function is such that half the ion energy perpendicular to the magnetic field is greater than the ion energy parallel to the magnetic field. This is just opposite to the case for upward auroral-current regions. These results are compared to recent particle-in cell simulations and FREJA satellite data

Keywords

ionosphere; magnetosphere; Alfven-Falthammar formula; Birkeland current; downward auroral-current region; electric current; ion distribution function; ionosphere; magnetosphere; negative parallel E-field; parallel E-field; theory; upward auroral-current region; velocity-space anisotropy; Anisotropic magnetoresistance; Boundary conditions; Distribution functions; Equations; Ionosphere; Magnetic fields; Magnetosphere; Physics; Plasma simulation; Satellites;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.902216

Filename

902216