Research
I am a graduate student doing research in plasma physics on Columbia University's HBT-EP experiment. "HBT-EP" stands for "High-Beta Tokamak-Extended Pulse." Our plasmas are confined by magnetic fields and "beta" is a number that we use to quantify the pressure of a plasma per unit of magnetic field: high-beta means high plasma pressure.
The word "tokamak" is a Russian acronym that refers to a particular kind of plasma confinement device. Tokamak plasmas are confined to a torus (donut) shaped volume by a relatively strong magnetic field pointing the long way around the torus and a somewhat weaker field generated by driving an electrical current in the plasma itself.
My work involves using active feedback to suppress tokamak plasma instabilities called external kink modes that arise at high beta. When limits for the plasma pressure are tested, the external kink mode can cause a plasma disruption, or sudden loss of confinement. Stable, high pressure plasmas are desirable because plasma fusion reactors will achieve higher energy output at higher values of beta.
Peer-reviewed journal publications
J. M. Hanson, B. DeBono, R. W. James, J. P. Levesque, M. E. Mauel, D. A. Maurer, G. A. Navratil, T. Sunn Pedersen, D. Shiraki, "Feedback suppression of rotating external kink instabilities in the presence of noise," Physics of Plasmas 15, 080704 (2008).
T. Sunn Pedersen, D.A. Maurer, J. Bialek, O. Katsuro-Hopkins, J. M. Hanson, M. E. Mauel, R. James, Y. Liu, and G. A. Navratil, "Experiments and modelling of external kink mode control using modular internal feedback coils", Nuclear Fusion 47, 1293-1299 (2007).
