Christopher Cothran

Research

My research activities are focused on experimental plasma physics with applications in fusion energy science and astrophysics. I am interested in the properties of magnetized plasmas other than the tokamak concept for magnetic confinement, in particular the spheromak, reversed-field pinch (RFP), and field-reversed configuration (FRC). The spheromak and RFP exhibit particularly interesting dynamics, often characterized as self-organization, in which the plasma turbulently relaxes to a state of minimum magnetic energy constrained by the conservation of its total magnetic helicity. In addition to their possible use for fusion, these plasmas have astrophysical relevance: prominences in the solar corona and magnetic clouds in the interplanetary medium appear to be relaxed states. Essential to the relaxation dynamics is a process, known as magnetic reconnection, which "cuts" magnetic field lines and rejoins them such that the global topology of the magnetized plasma changes. The magetic energy convected into a reconnection region is converted to thermal energy and back-to-back high velocity outflowing jets of plasma. Reconnection is thought to be at the heart of the violent explosions in the solar corona known as solar flares, and the reason why the corona is nearly a thousand times hotter than the photosphere!

Courses: Fall 2007, Haverford

Courses: Spring 2008, Haverford