Drew Chap

chap-drew
PhD Student

Department of Aerospace Engineering
2101 Glenn L. Martin Wind Tunnel
University of Maryland
College Park, Maryland 20742
Graduate Research Assistant
Space Power and Propulsion Laboratory
Phone: (301) 405-8562 | E-mail: amchap06 (at) gmail.com

Research Interests

Numerical simulations of plasmas, parallel computing, fusion power generation, direct energy conversion

Thesis Topic

Numerical Modeling of Ion Packet Thermalization in an IEC Device

Abstract

The viability of a multiple grid pulsed inertial electrostatic confinement (IEC) fusion device for power generation is dependent in part on the average confinement time of the cycling ions. Increasing the ion confinement time decreases energy loss, necessary for making a net power IEC fusor possible. A hybrid particle-in-cell (hybrid PIC) model to simulate the pulsed IEC plasma to the thermalization timescale is being developed to analyze the long term stability of the ion bunches and serve as a test bed for methods to increase ion bunching and confinement. These methods include: the focusing of ion beams with multiple electrostatic focusing grids, the construction of the potential well to encourage the bunching of ions, the acceleration of bunched ions by means of time-varying voltages on electrostatic grids, and the magnetic confinement of electrons to neutralize the ion beam paths and core. The modeling of the IEC plasma presents many challenges: the assumption of quasineutrality does not hold, the plasma does not reach thermal equilibrium, and there is no steady state. The hybrid PIC model simulates ions as macroparticles and electrons as a massless thermalized fluid. The bulk motion of the electron fluid is influenced by the magnetic fields through consideration of the magnetic mobility tensor and is modeled as a steady state that evolves in accordance with the ion movements. The Scharfetter-Gummel method is used for the discretization of the electron flux and semi-analytic method for the simultaneous solution to the electron density and electric potential is employed. A 2-D axisymmetric (r-z) geometry is being considered as the modeling domain for a single beam path within the IEC.