Jan Egedal, MIT
Magnetic Reconnection in Plasmas; a Celestial Phenomenon in the Laboratory
Magnetic reconnection in a low collisional regime is studied on the Versatile Toroidal
Facility (VTF) at MIT. The detailed evolution of the profiles of plasma density, current
density, and electrostatic potential at the onset of driven reconnection is measured
experimentally. The VTF device facilitates experiments with two distinct sets of boundary
conditions: an "open" configuration for which the field lines intersect the vacuum vessel
walls, and a "closed" configuration for which the magnetic field lines form closed loops
inside the device. For the open configuration our studies reveal a new mechanism -
particle trapping - responsible for fast reconnection. This mechanism is found to be
consistent with unique spacecraft observations deep in the Earth's magnetotail. In the
talk I will discuss our experimental observations of magnetic reconnection in the open
configuration, provide a theoretical explanation, and apply the theory to the spacecraft
observations. I will also discuss preliminary results from the closed configuration.
|