Physics and Astronomy Colloquium - Dr. Matt Landreman - University of Maryland
Title: "Breaking Axisymmetry in Magnetized Plasmas"
Abstract: Symmetry is important in many areas of physics, and plasma physics is one such area. For instance, the trajectories of charged particles in a plasma are fundamentally different in axisymmetric versus nonaxisymmetric magnetic fields - meaning fields with or without continuous rotational symmetry - due to the constraint of canonical angular momentum conservation implied by the symmetry. Magnetic fields can possess a hidden “quasi-symmetry” in which particle trajectories resemble those in a symmetric field, even though the field appears highly asymmetric in Cartesian coordinates. Symmetry-breaking in plasmas has many consequences, such as causing high-Z elements to be drawn into toroidal plasmas. Understanding of asymmetry is important for both laboratory and space plasma physics, as even nominally axisymmetric plasmas inevitably have departures from perfect axisymmetry.