Recovery of electron sheath current in magnetically self-insulated transmission lines

Journal Article · Thu Sep 01 04:00:00 EDT 1983 · IEEE Trans. Plasma Sci.; (United States)

DOI:https://doi.org/10.1109/TPS.1983.4316254· OSTI ID:5002023

Crow, J T; Peterson, G D

Magnetically self-insulated lines operating at high electric field stress have a high percentage of the current flow in an electron sheath adjacent to the cathode. Recovery of the current in this sheath is desirable for efficient power transport. The Sandia National Laboratories HydraMITE accelerator has a magnetically insulated transmission line (MITL) which has a 7.6-..cap omega.. geometric impedance and operates at 4.8 ..cap omega.., indicating that approximately 40 percent of the current flows in the electron sheath. If this line is terminated in a section of higher impedance line, theory and simulations indicate that the electron sheath current will be lower at the output. This higher impedance section, however, is effectively an inductance across which there is a voltage drop during the rising part of the pulse. An experiment was conducted on the HydraMITE machine in which input and output currents were measured on a section of line which the impedance changed smoothly from 7.6 ..cap omega.. to 20 ..cap omega... At the output the electron current was a few percent of the total current. Measurements were made with a range of inductive and resistive loads. The input and output currents were then compared to lumped circuit line simulations to separate losses related to inductance from electron sheath losses. The measurements indicate that a percentage of the electron sheath is recovered which depends on the load impedance and that the recovery is more efficient after the pulse voltage peak where potential drop along the increased impedance line aids retrapping of electrons.

• Research Organization: Sandia National Laboratories, Albuquerque, NM 87185
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5002023
• Journal Information: IEEE Trans. Plasma Sci.; (United States), Journal Name: IEEE Trans. Plasma Sci.; (United States) Vol. 11:3; ISSN ITPSB
• Country of Publication: United States
• Language: English

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70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700203* -- Fusion Power Plant Technology-- Power Supplies
Energy Storage
ACCELERATORS
CATHODES
CURRENTS
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRIC POTENTIAL
ELECTRODES
ELECTRON DENSITY
ENERGY LOSSES
IMPEDANCE
LOSSES
MAGNETIC INSULATION
NATIONAL ORGANIZATIONS
POWER LOSSES
POWER TRANSMISSION LINES
SANDIA LABORATORIES
STRESSES
US AEC
US DOE
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