the hard question - how do reconnection physics and macroscale dynamics cooperate in determining...

The Hard Question -How do Reconnection Physics and Macroscale Dynamics Cooperate in

Determining Global System Behavior?

● For example, in the case of CMEs and substorms does rapid macroscale motion precede rapid reconnection or vice versa?

● In the case of the interaction between the solar wind and the magnetosphere is the transpolar voltage set by local reconnection physics or by a whole body interaction?

● Or do reconnection physics and macroscale dynamics interactively determine the outcome?

Forbes CME model

Regarding CMEs, a macroscale instability leads to reconnection in the Forbes model

Hones substorm model

The community conceptual model of a substorm hasslow evolution leading to the onset of rapid reconnection

Time = 2:14 Time = 2:22 Time = 2:24

Triggered Substorm Using OpenGGCM at CCMC

What do macroscale MHD simulations say in this case?

Does rapid reconnection precede motion or vice versa?

Vice versa

Axford Conjecture

• Reconnection takes place at a rate determined by external boundary conditions.

• Examples: Dayside magnetopause reconnection CME reconnection (some models)

-33 kV 33 kV

ISM-MHD

IMF Clock Angle 180o

Potential

Weimer-Empirical

Empirical ~ 1.1 x ISM-MHD

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