Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520983
Title: Experimental study of radiatively cooled magnetically driven plasma jets
Author: Suzuki Vidal, Francisco Andres
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2009
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Abstract:
This thesis presents the results of experiments to study the formation and dynamics of plasma jets in the laboratory, in particular their scaling to astrophysical jets. The experiments were performed on the MAGPIE generator, which delivered a peak current of 1 MA in 250 ns. A variety of plasma diagnostics allowed the dynamics of the jets to be studied and the conditions of the plasma to be determined. Radial wire array experiments were performed in which the mass of the wires and the magnitude of the toroidal magnetic field was varied. These results show that it is possible to control the time of formation and the expansion velocity of the magnetically driven jet that characterizes this configuration. In addition, the experiments allowed the introduction of a poloidal magnetic field into the radial wire array with the aim of studying its effect on the dynamics and stability of the plasma jet. The radial foil is introduced as a novel configuration to produce episodic magnetic-tower jets. Magnetic cavities were observed to emerge in timescales of ~ 30 ns, with increasing expansion velocities reaching ~ 300 km/s. The formation of episodic magnetically driven jets occurs due to reconnection of current at the base of the cavity, allowing 3-4 episodes to be produced per experiment. Results allowed the energy balance, the magnitude of the trapped toroidal magnetic field, and the characteristic temperatures in these outflows to be determined, as well as other plasma parameters. This experimental setup allowed the study of the interaction of episodic jets with an ambient medium by introducing a neutral gas above the foil. The dynamics of the formation of several shock structures at early times was studied, opening new possibilities for laboratory astrophysics experiments in the future.
Supervisor: Lebedev, Sergey Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.520983  DOI: Not available
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