The Field-Aligned Current Versus Electric Potential Relation and Auroral Electrodynamics

  1. S.-I. Akasofu and
  2. J.R. Kan
  1. L. R. Lyons

Published Online: 26 MAR 2013

DOI: 10.1029/GM025p0252

Physics of Auroral Arc Formation

Physics of Auroral Arc Formation

How to Cite

Lyons, L. R. (1981) The Field-Aligned Current Versus Electric Potential Relation and Auroral Electrodynamics, in Physics of Auroral Arc Formation (eds S.-I. Akasofu and J.R. Kan), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM025p0252

Author Information

  1. Space Environment Laboratory, Noaa, Boulder, Colorado 80303, USA

Publication History

  1. Published Online: 26 MAR 2013
  2. Published Print: 1 JAN 1981

ISBN Information

Print ISBN: 9780875900506

Online ISBN: 9781118664360



  • Auroras—Addresses, essays, lectures


Observations over aurora are inconsistent with the concept that instabilities leading to anomalous resistivity govern the relation between the field-aligned current density j and the field-aligned potential difference V|. The observations are also inconsistent with the analogy to laboratory double layers that significant V|'s result from j| reaching a critical value that cannot be exceeded. However, the observed magnitudes of j| and V over aurora, and the observed relation'between them, are quantitatively explained by considering nothing more than the uninhibited, single-particle motion along field lines. It is shown that the j| versus V| relation from single-particle motion, together with the ionospheric current continuity equation, can account for the overall electrodynamics (i.e., particle acceleration, precipitating electron energy fluxes, currents, and electric potentials) of large scale “inverted-V” (∼200 km in latitudinal width) and discrete auroral (∼10'S km in latitudinal width) precipitation regions. The inverted-V scale size is a natural result of the current versus electric potential relations along field lines and in the ionosphere, whereas the discrete auroral scale size results from specific structure in the electric potential distribution deep within the magnetosphere.