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Title:  The VelocitySpace Particle Loss in FieldReversed Theta Pinches 
Author(s):  Hsiao, MingYuan 
Department / Program:  Nuclear Engineering 
Discipline:  Nuclear Engineering 
Degree Granting Institution:  University of Illinois at UrbanaChampaign 
Degree:  Ph.D. 
Genre:  Dissertation 
Subject(s):  Engineering, Nuclear 
Abstract:  A fieldreversed theta pinch (FRTP) is a compact device for magnetic fusion. It has attracted much attention in recent years since encouraging experimental results have been obtained. However, the definite causes for the observed particle loss rate and plasma rotation are not well known. In this work, we study the velocityspace particle loss (VSPL), i.e., particle loss due to the existence of a loss region in velocity space, in FRTP's in order to have a better understanding about the characteristics of this device. Based on two constants of motion, H and P(,(theta)), where H is the total energy of a particle and P(,(theta)) is the canonical angular momentum, particle confinement criteria are derived, which impose constraints on H and P(,(theta)). It is found that only a portion of (H,P(,(theta))) space, or equivalently, of velocity space, is for confinement. A loss region in velocity space is found. Effects of this loss region in velocity space are investigated. The velocityspace particle loss due to collisions is calculated from the FokkerPlanck equation. The scaling law for particle confinement is obtained. Without assuming any instability, the particle confinement time based on VSPL theory alone can account for the experimentally observed particle confinement time. This shows the importance of the velocityspace particle loss. For the velocity distribution in collisional equilibrium, a simple analytical expression, V(,0), is verified to be a good representation of the actual velocity distribution in the presence of the loss region in velocity space. In steadystate, simple analytical approximate solutions for the whole particle distribution function, f(r,v), are obtained, from which the characteristics of the FRTP plasmas can be known. It is shown that the VSPL model can account for the experimental observation in density profiles, particle confinement time, occurrence and spinup of plasma rotation. Therefore, the VSPL has the possibility to be the dominant particle loss mechanism and the sole cause responsible for the observed plasma rotation in FRTP's. 
Issue Date:  1983 
Type:  Text 
Description:  178 p. Thesis (Ph.D.)University of Illinois at UrbanaChampaign, 1983. 
URI:  http://hdl.handle.net/2142/70894 
Other Identifier(s):  (UMI)AAI8409959 
Date Available in IDEALS:  20141216 
Date Deposited:  1983 
This item appears in the following Collection(s)

Dissertations and Theses  Nuclear, Plasma, and Radiological Engineering

Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois