Chin, Robert (2012) Nonlinearity in thermally active and rotating plasmas. PhD thesis, University of Warwick.

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Abstract

The wide reaching nature of plasma physics will be studied here, with the applications
of both the large scale, of solar plasma physics and then decreasing by many orders of
magnitude to the laboratory plasma, of magnetically confined fusion experiments.
Part I
The nonlinear evolution of magnetoacoustic waves in a nonadiabatic plasma are investigated
analytically. The effect of plasma activity due to linear and quadratic heating and
radiative cooling on propagating magnetoacoustic waves in a uniform plasma are considered.
A non-linear evolution equation is derived and stationary solutions are looked for the
various combination of signs of the linear and quadratic heating-cooling terms, which determine
the thermal activity of the plasma. It is shown that self-organizing magnetoacoustic
waves (autowaves) exist in an active plasma. These wave have amplitudes that are independent
from the initial conditions and function of plasma properties only. Their potential
diagnostic purposes are discussed. Furthermore, magnetoacoustic auto-solitary waves are
shown to exist. They have been modelled using a novel perturbative technique which allows
to determine their propagation speed and shape.
Part II
Equilibria of MAST-like plasmas with transonic toroidal flows are calculated numerically
in the framework of two-fluid theory [Thyagaraja and McClements, 2006] using a fixedboundary
equilibrium solver, GRASS.In the non-dissipative limit, with momentum sources
neglected, two-fluid analysis leads to interdependence between the rotation, temperature
and density profiles, and the possibility of a departure from rigid-body rotation of flux surfaces.
The effects of toroidal flows on the position of the magnetic axis, the plasma safety
factor profile and the density profile are determined for a range of scenarios, including rigid
body rotation. The electron temperature and ion temperature are assumed to be flux functions,
with profiles that are broadly consistent with measurements from MAST.
This thesis will also highlight the differences, or indeed similarities, of plasma from the
astrophysical to the laboratory world.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QC Physics
Library of Congress Subject Headings (LCSH):	Plasma dynamics
Official Date:	July 2012
Dates:	Date Event July 2012 Submitted
Institution:	University of Warwick
Theses Department:	Department of Physics
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Verwichte, E. (Erwin)
Extent:	xi, 138 p. : charts
Language:	eng
URI:	http://wrap.warwick.ac.uk/id/eprint/50051

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