Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma
- Oak Ridge, TN
- Kingston, TN
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.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Number(s):
- US 4755345
- OSTI ID:
- 866642
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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/