Representation of Magnetic Field in Space: Field Line Topology and Flux Surfaces

Dr. Brahmananda Dasgupta

Center for Space Plasma and Aeronomic Research
UA Huntsville

October 16, 2009
219 Shelby Center
3:00 (Refreshements at 2:30)

Abstract

Magnetic field permeates the space around us; it drenches interplanetary, interstellar and intergalactic space and plays a key role. In this presentation, we first summarize several descriptions of magnetic field, their individual properties and associated problems, particularly emphasizing the representation of magnetic field by Euler (or Clebsch) potential. We introduce the concept of magnetic helicity, which provides the most elementary description of topology of field lines in terms of their linkage. Next, we describe our recent works on generation of chaotic magnetic field by asymmetric current configurations, and indicate that onset of such chaotic magnetic field lines are characterized by the destruction of magnetic (flux) surfaces. It is argued that such chaotic magnetic field lines should occur frequently in nature. In this context, magnetic field line Hamiltonian, integrability of 3-D magnetic field line equations and problems of representing such chaotic magnetic field line by Euler potentials are briefly discussed.