Narrow auroral arc notes

June 1, 2012

magnetic bottle: pitch angle distribution vs. mirror height equipotential lines -> parallel E-field (Stephen Knight 1970) -> Large scale, dull auroral arc

• inertial alfven wave connection to parallel E-field

fine scale arcs assosciated with Farley-Buneman instabilities, GPS scintillation

energy to produce electron-ion pair ionization potential ~ 18 eV takes on average ~ 35 eV

energy deposition physics

single particle motion, 3 adiabatic invariants, Debye length, two fluid vector potential

Alfven wave can couple to whistler mode

Auroral emissions: Bohr model of atom. have to release energy gap between orbitals (work function). Vibrational modes

Ions: closure current electrons: field aligned current

Inertial alfven wave: electron mass matters due to phase speed > speed of light F=ma inertial limit inerital lag – prevents group velocity from exceeding speed of light

λ_e = c / ω_pe electron skin depth confines wave

Auroral emissions:

Björn Gustavsson Ph.D. thesis discusses briefly specifics of four major auroral emission lines.

Thesis on kinetic reactions resulting in auroral emissions.

Auroral width:

• Borovsky 1993 “Auroral arc thicknesses as predicted by various theories”, JGR: Space Physics.
• Chaston 2003 “Width and brightness of auroral arcs driven by inertial Alfven waves”, JGR: Space Physics.

Books:

• Chen
• Kivelson and Russell
• Cravens
• Nagey