Dispersive Waves and Magnetic Reconnection

Alex Flanagan (University of Wisconsin)J. F. Drake (UMD), M. Swisdak (UMD)

Magnetic Reconnection?

• Magnetic energy converted to kinetic and thermal energy

• Occurs in solar corona, magnetosphere, laboratory plasma experiments, and even at edge of solar system

Generalized Ohm’s Law

Hall term = whistler wavesElectron pressure gradient = kinetic Alfvén waves

Dispersive WavesLinear waves: Dispersive waves:

Sweet-Parker v Fast Reconnection

Reconnection Rate

Sweet-Parker reconnection:

Fast reconnection:

PIC SimulationsKinetic Particle-in-Cell Simulations

Look for:• Size and scaling of dissipation region• Scaling of reconnection rate• Actual reconnection rate of system

Conclusions

• Magnetic reconnection is fast in parameter regimes where dispersive waves are possible

• There is not a sharp transition between fast and slow reconnection

• The parameters we use are similar to those found in solar wind and solar corona

References• Birn, J. et al “Geospace Environmental Modeling (GEM) Magnetic Reconnection Challenge”

Journal of Geophysical Research (2001)

• Cassak, P. “Catastrophe Model for the Onset of Fast Magnetic Reconnection” Phd Thesis (2006)

• Mandt, M. “Transition to Whistler Mediated Magnetic Reconnection” Geophysical Research Letters (1994)

• Rodgers, B. “Role of Dispersive Waves in Collisionless Magnetic Reconnection” Physical Review Letters (2001)

• Shay, M. “Two-Scale Structure of the Electron Dissipation Region Collisonless Magnetic Reconnection” Physical Review Letters (2007