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Title: Axial mass fraction measurements in a 300kA dense plasma focus

The dynamics and characteristics of the plasma sheath during the axial phase in a ~300 kA, ~2 kJ dense plasma focus using a static gas load of Ne at 1–4 Torr are reported. The sheath, which is driven axially at a constant velocity ~10 5 m/s by the j × B force, is observed using optical imaging, to form an acute angle between the electrodes. This angle becomes more acute (more parallel to the axis) along the rundown. The average sheath thickness nearer the anode is 0.69 ± 0.02 mm and nearer the cathode is 0.95 ± 0.02 mm. The sheath total mass increases from 1 ± 0.02 μg to 6 ± 0.02 μg over the pressure range of 1–4 Torr. However, the mass fraction (defined as the sheath mass/total mass of cold gas between the electrodes) decreases from 7% to 5%. In addition, the steeper the plasma sheath, the more mass is lost from the sheath, which is consistent with radial and axial motion. Lastly, experimental results are compared to the Lee code when 100% of the current drives the axial and radial phase.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ; ORCiD logo [3] ;  [4]
  1. Univ. of California, San Diego, CA (United States). Center for Energy Research
  2. Alameda Applied Sciences Corporation, San Leandro, CA (United States)
  3. Evergreen Hill Sciences, Philomath, OR (United States)
  4. Imperial College London, South Kensington, London (United Kingdom)
Publication Date:
Grant/Contract Number:
SC0010751
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 9; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of California, San Diego, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1467900
Alternate Identifier(s):
OSTI ID: 1325303

Caballero Bendixsen, L. S., Bott-Suzuki, S. C., Cordaro, S. W., Krishnan, M., Chapman, S., Coleman, P., and Chittenden, J.. Axial mass fraction measurements in a 300kA dense plasma focus. United States: N. p., Web. doi:10.1063/1.4962679.
Caballero Bendixsen, L. S., Bott-Suzuki, S. C., Cordaro, S. W., Krishnan, M., Chapman, S., Coleman, P., & Chittenden, J.. Axial mass fraction measurements in a 300kA dense plasma focus. United States. doi:10.1063/1.4962679.
Caballero Bendixsen, L. S., Bott-Suzuki, S. C., Cordaro, S. W., Krishnan, M., Chapman, S., Coleman, P., and Chittenden, J.. 2016. "Axial mass fraction measurements in a 300kA dense plasma focus". United States. doi:10.1063/1.4962679. https://www.osti.gov/servlets/purl/1467900.
@article{osti_1467900,
title = {Axial mass fraction measurements in a 300kA dense plasma focus},
author = {Caballero Bendixsen, L. S. and Bott-Suzuki, S. C. and Cordaro, S. W. and Krishnan, M. and Chapman, S. and Coleman, P. and Chittenden, J.},
abstractNote = {The dynamics and characteristics of the plasma sheath during the axial phase in a ~300 kA, ~2 kJ dense plasma focus using a static gas load of Ne at 1–4 Torr are reported. The sheath, which is driven axially at a constant velocity ~105 m/s by the j × B force, is observed using optical imaging, to form an acute angle between the electrodes. This angle becomes more acute (more parallel to the axis) along the rundown. The average sheath thickness nearer the anode is 0.69 ± 0.02 mm and nearer the cathode is 0.95 ± 0.02 mm. The sheath total mass increases from 1 ± 0.02 μg to 6 ± 0.02 μg over the pressure range of 1–4 Torr. However, the mass fraction (defined as the sheath mass/total mass of cold gas between the electrodes) decreases from 7% to 5%. In addition, the steeper the plasma sheath, the more mass is lost from the sheath, which is consistent with radial and axial motion. Lastly, experimental results are compared to the Lee code when 100% of the current drives the axial and radial phase.},
doi = {10.1063/1.4962679},
journal = {Physics of Plasmas},
number = 9,
volume = 23,
place = {United States},
year = {2016},
month = {9}
}