Ion coupling efficiency for an extraction applied-B ion diode on the HELIA linear-induction adder in positive polarity
- Sandia National Labs., Albuquerque, NM (United States)
This paper reports on initial experiments to investigate coupling of the four-stage HELIA linear-induction accelerator (3.6 MV, 180 kA, 30 ns FWHM) to a uniformly insulated applied-B ion diode in planar extraction geometry. Extraction of an annular ion beam parallel to the diode axis for ion transport and focusing experiments requires the HELIA operate in positive (reverse) polarity, where each of the four cathode voltage adder sections contributes a group of electrons of unique energy and canonical angular momentum to electron flow in a magnetically insulated transmission line (MITL). We show that a number of requirements must be meet for the efficient production of a uniform high intensity ion beam. An appropriate insulating magnetic field geometry is needed to provide uniform insulation of the anode ion-emitting surface and reduce direct electron losses from the cathode MITL region to the anode. A flat diode impedance profile with D{sub D} {lt} Z{sub SELF-LIMITED} is required for efficient MITL power coupling to the diode. Even when the MITL is efficiently insulated upstream of the diode, we observe that some flow (MITL sheath) electrons are lost directly to the anode along flux lines of the diode-insulating magnetic field.
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5627257
- Journal Information:
- IEEE Transactions on Plasma Science (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Transactions on Plasma Science (Institute of Electrical and Electronics Engineers); (United States) Vol. 19:5; ISSN ITPSB; ISSN 0093-3813
- Country of Publication:
- United States
- Language:
- English
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