Keiling et al. ‘03

Visible FUV

Downward Poynting

Flux

UpwardPoynting Flux

Auroral Morphologyas seen in

Occurrence of Upward Ion Beams Near 1RE Altitude

(Polar TIMAS)

Collin et al. ‘98

Car

lso

n e

t al

. ‘0

1

Alfvén Wave Induced Outflow

AuroralLuminosity

Downward AlfvénPoynting Flux

Upward IonBeams

Liou et al. ‘97

Keiling et al. ‘03

Collin et al. ‘98

OUTFLOW

Str

ang

ew

ay e

t al.

’02

Li and Temerin ‘93

Auroral substorms & geomagnetic storms

Hypothesis (McFadden)

• Substorms deposit EM energy at low altitude.

• Ionosphere expands, promoting intense ion outflows.

• Stormtime electric fields force outflowing ions into near-earth plasmasheet.

• Betatron acceleration energizes earthward convecting ions.

• The now prodigious, energetic ions further energize the ring current, intensifying the storm.