Axford Conjecture

• Reconnection takes place at a rate determined by external boundary conditions (microphysics versus macrophysics)

• Examples: Dayside magnetopause reconnection Tail reconnection CME reconnection

BA

-33 kV 33 kV

ISM-MHD

IMF Clock Angle 180o

Potential

Weimer-Empirical

Empirical ~ 1.1 x ISM-MHD

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0 5 10 15 20 25 30 35 40

Skill Scores December 98

Winglee/skillRidley/skillRaeder/skillWeimer/skill

Wiltberger/skill

pass #

GEM Metrics Grand Challenge (Hesse Compilations)

Raeder: 0.63Weimer: 0.61Ridley: 0.50

A Particularly Good Case

models appear to match smoothed vy (100s) best

-1

-0.5

0

0.5

1

1.5

72200 72400 72600 72800 73000 73200 73400

DMSP data-model comparisona1398344.195

vDMSPRidleyRaederWeimer

time

Hones substorm model

Forbes CME model