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Title: Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma

Abstract

A resonant double loop radio frequency (rf) antenna for radiating high-power rf energy into a magnetically confined plasma. An inductive element in the form of a large current strap, forming the radiating element, is connected between two variable capacitors to form a resonant circuit. A real input impedance results from tapping into the resonant circuit along the inductive element, generally near the midpoint thereof. The impedance can be matched to the source impedance by adjusting the separate capacitors for a given tap arrangement or by keeping the two capacitances fixed and adjustng the tap position. This results in a substantial reduction in the voltage and current in the transmission system to the antenna compared to unmatched antennas. Because the complete circuit loop consisting of the two capacitors and the inductive element is resonant, current flows in the same direction along the entire length of the radiating element and is approximately equal in each branch of the circuit. Unidirectional current flow permits excitation of low order poloidal modes which penetrate more deeply into the plasma.

Inventors:
 [1];  [1];  [2]
  1. (Oak Ridge, TN)
  2. (Kingston, TN)
Issue Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
OSTI Identifier:
866642
Patent Number(s):
4755345
Assignee:
United States of America as represented by United States (Washington, DC) ORNL
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
impedance; matched; high-power; rf; antenna; cyclotron; resonance; heating; plasma; resonant; double; loop; radio; frequency; radiating; energy; magnetically; confined; inductive; element; form; current; strap; forming; connected; variable; capacitors; circuit; input; results; tapping; near; midpoint; source; adjusting; separate; tap; arrangement; keeping; capacitances; fixed; adjustng; position; substantial; reduction; voltage; transmission; compared; unmatched; antennas; complete; consisting; flows; direction; entire; length; approximately; equal; branch; unidirectional; flow; permits; excitation; poloidal; modes; penetrate; deeply; rf antenna; confined plasma; resonant circuit; approximately equal; entire length; radio frequency; current flow; cyclotron resonance; rf energy; magnetically confined; current flows; inductive element; substantial reduction; radiating element; unidirectional current; high-power rf; input impedance; impedance matched; source impedance; /376/313/315/333/343/

Citation Formats

Baity, Jr., Frederick W., Hoffman, Daniel J., and Owens, Thomas L. Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma. United States: N. p., 1988. Web.
Baity, Jr., Frederick W., Hoffman, Daniel J., & Owens, Thomas L. Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma. United States.
Baity, Jr., Frederick W., Hoffman, Daniel J., and Owens, Thomas L. Fri . "Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma". United States. https://www.osti.gov/servlets/purl/866642.
@article{osti_866642,
title = {Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma},
author = {Baity, Jr., Frederick W. and Hoffman, Daniel J. and Owens, Thomas L.},
abstractNote = {A resonant double loop radio frequency (rf) antenna for radiating high-power rf energy into a magnetically confined plasma. An inductive element in the form of a large current strap, forming the radiating element, is connected between two variable capacitors to form a resonant circuit. A real input impedance results from tapping into the resonant circuit along the inductive element, generally near the midpoint thereof. The impedance can be matched to the source impedance by adjusting the separate capacitors for a given tap arrangement or by keeping the two capacitances fixed and adjustng the tap position. This results in a substantial reduction in the voltage and current in the transmission system to the antenna compared to unmatched antennas. Because the complete circuit loop consisting of the two capacitors and the inductive element is resonant, current flows in the same direction along the entire length of the radiating element and is approximately equal in each branch of the circuit. Unidirectional current flow permits excitation of low order poloidal modes which penetrate more deeply into the plasma.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

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