Premium
‘Self‐consistent’ production of ion conics on return current region auroral field lines: A time‐dependent, semi‐kinetic model
Author(s) -
Brown David G.,
Wilson Gordon R.,
Horwitz James L.,
Gallagher Dennis L.
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl02244
Subject(s) - physics , ion , atomic physics , electron , instability , kinetic energy , particle acceleration , field line , diffusion , plasma , electric field , range (aeronautics) , materials science , nuclear physics , mechanics , quantum mechanics , thermodynamics , composite material
We describe initial results from a time‐dependent, semi‐kinetic model of plasma outflow incorporating wave‐particle interactions along current‐carrying auroral field lines. Electrostatic waves are generated by the current driven ion cyclotron instability (CDICI), causing perpendicular velocity diffusion of ions plus electron heating via anomalous resistivity when and where the relative drift between electrons and ions exceeds certain critical velocities. Using the local bulk parameters we calculate these critical velocities, and so are able to self‐consistently switch on and off the heating of the various particle species. Due to the dependence of these critical velocities on the bulk parameters of the species the heating effects exhibit quite complex spatial and temporal variations. A wide range of ion distribution functions are observed in these simulations, including conics with energies of a few electron volts and ‘ring’ distributions. The rings are seen to be a natural result of transverse heating and velocity filter effects and do not require coherent acceleration processes. We also observe the formation of a density depletion in hydrogen and enhanced oxygen densities at high altitudes.