Compression mechanisms in the plasma focus pinch

The compression of the plasma focus pinch is a dynamic process, governed by the electrodynamics of pinch elongation and opposed by the negative rate of change of current dI/dt associated with the current dip. The compressibility of the plasma is influenced by the thermodynamics primarily the speci...

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Main Authors: Lee, S., Saw, S. H., Jalil, Ali
Format: Article
Language:English
Published: AIP Publishing 2017
Subjects:
Online Access:http://eprints.intimal.edu.my/762/
http://eprints.intimal.edu.my/762/1/Compression%20mechanisms%20in%20the%20plasma%20focus%20pinch.pdf
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author Lee, S.
Saw, S. H.
Jalil, Ali
author_facet Lee, S.
Saw, S. H.
Jalil, Ali
author_sort Lee, S.
building INTI Institutional Repository
collection Online Access
description The compression of the plasma focus pinch is a dynamic process, governed by the electrodynamics of pinch elongation and opposed by the negative rate of change of current dI/dt associated with the current dip. The compressibility of the plasma is influenced by the thermodynamics primarily the specific heat ratio; with greater compressibility as the specific heat ratio γ reduces with increasing degree of freedom f of the plasma ensemble due to ionization energy for the higher Z (atomic number) gases. The most drastic compression occurs when the emitted radiation of a high-Z plasma dominates the dynamics leading in extreme cases to radiative collapse which is terminated only when the compressed density is sufficiently high for the inevitable self-absorption of radiation to occur. We discuss the central pinch equation which contains the basic electrodynamic terms with built-in thermodynamic factors and a dQ/dt term; with Q made up of a Joule heat component and absorption-corrected radiative terms. Deuterium is considered as a thermodynamic reference (fully ionized perfect gas with f = 3) as well as a zero-radiation reference (bremsstrahlung only; with radiation power negligible compared with electrodynamic power). Higher Z gases are then considered and regimes of thermodynamic enhancement of compression are systematically identified as are regimes of radiation-enhancement. The code which incorporates all these effects is used to compute pinch radius ratios in various gases as a measure of compression. Systematic numerical experiments reveal increasing severity in radiation-enhancement of compressions as atomic number increases. The work progresses towards a scaling law for radiative collapse and a generalized specific heat ratio incorporating radiation.
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spelling intimal-7622017-04-17T01:36:16Z http://eprints.intimal.edu.my/762/ Compression mechanisms in the plasma focus pinch Lee, S. Saw, S. H. Jalil, Ali QC Physics The compression of the plasma focus pinch is a dynamic process, governed by the electrodynamics of pinch elongation and opposed by the negative rate of change of current dI/dt associated with the current dip. The compressibility of the plasma is influenced by the thermodynamics primarily the specific heat ratio; with greater compressibility as the specific heat ratio γ reduces with increasing degree of freedom f of the plasma ensemble due to ionization energy for the higher Z (atomic number) gases. The most drastic compression occurs when the emitted radiation of a high-Z plasma dominates the dynamics leading in extreme cases to radiative collapse which is terminated only when the compressed density is sufficiently high for the inevitable self-absorption of radiation to occur. We discuss the central pinch equation which contains the basic electrodynamic terms with built-in thermodynamic factors and a dQ/dt term; with Q made up of a Joule heat component and absorption-corrected radiative terms. Deuterium is considered as a thermodynamic reference (fully ionized perfect gas with f = 3) as well as a zero-radiation reference (bremsstrahlung only; with radiation power negligible compared with electrodynamic power). Higher Z gases are then considered and regimes of thermodynamic enhancement of compression are systematically identified as are regimes of radiation-enhancement. The code which incorporates all these effects is used to compute pinch radius ratios in various gases as a measure of compression. Systematic numerical experiments reveal increasing severity in radiation-enhancement of compressions as atomic number increases. The work progresses towards a scaling law for radiative collapse and a generalized specific heat ratio incorporating radiation. AIP Publishing 2017 Article PeerReviewed text en http://eprints.intimal.edu.my/762/1/Compression%20mechanisms%20in%20the%20plasma%20focus%20pinch.pdf Lee, S. and Saw, S. H. and Jalil, Ali (2017) Compression mechanisms in the plasma focus pinch. AIP Conference Proceedings, 1824 (1). 10.1063/1.4978814
spellingShingle QC Physics
Lee, S.
Saw, S. H.
Jalil, Ali
Compression mechanisms in the plasma focus pinch
title Compression mechanisms in the plasma focus pinch
title_full Compression mechanisms in the plasma focus pinch
title_fullStr Compression mechanisms in the plasma focus pinch
title_full_unstemmed Compression mechanisms in the plasma focus pinch
title_short Compression mechanisms in the plasma focus pinch
title_sort compression mechanisms in the plasma focus pinch
topic QC Physics
url http://eprints.intimal.edu.my/762/
http://eprints.intimal.edu.my/762/
http://eprints.intimal.edu.my/762/1/Compression%20mechanisms%20in%20the%20plasma%20focus%20pinch.pdf