Investigation of resonance excitation and Cerenkov damping of high-frequency plasma oscillations

Journal Article · Sun Dec 01 04:00:00 EST 1963 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/3/4/004· OSTI ID:4066164

Nazarov, N. I.; Ermakov, A. I.; Dolgopolov, V. V.; Stepanov, L. N.; Tolok, V. T.

Resonance excitation and the damping mechanism of highfrequency- oscillations of a plasma cylinder in an external magnetic field were investigated. Wave excitation was accomplished with a system of external coils creating a spatially periodic electromagnetic field with a period lambda /sub 0/ = 15 cm. The operating frequency (f = 10 MHz) was considerably smaller than the electron cyclotron frequency ( omega approximately /sup Mm/He/200) and greater than the ion cyclotron frequency. It was shown that the oscillations penetrate well into the plasma. The wavelength measured along the direction of the magnetic field lambda /sub z/ coincides with the period of the exciting coil lambda /sub 0/ and corresponds to the length of the wave that is defined from the dispersion ratio for these oscillations. The direction of the rotation of the wave coincides with the direction of the rotation of the electron in a magnetic field. The measured damping length of the wave was 1 = 40 cm. Plasma density was n/sub 0/ approximately 5 x 10/sup 13/ ions/cm/sup 3/, electron temperature was T/sub e/ approximately 50 ev, and the wavelength in the damping region was lambda = 10 cm. Wave damping length due to collisions was l/sub st/ approximately lambda / sub z/ omega /sup He//2 pi nu ( nu is the frequency o f collisions between electrons and ions) of the order of 10/sup 4/ cm, which exceeds the value measured by more than a hundred times. Damping length due to the collisionless Cherenkov mechanism is l/sub L/ approximately ( lambda /sub z//2 pi )/sup 2/ (m/ T/sub e/)/sup 1/2/ p Mm /He = 60 cm, which compares well with the value measured. On these grounds the conclusion is drawn that the observed damping is caused by the collisionless Cherenkov mechanism.

• Research Organization: Khar'kov Inst. of Physics and Tech.
• Sponsoring Organization: USDOE
• NSA Number: NSA-18-017154
• OSTI ID: 4066164
• Journal Information: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 4 Vol. 3; ISSN 0029-5515
• Publisher: IOP Science
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANIONS
ARGON
ATOMS
CHERENKOV RADIATION
COILS
COLLISIONS
CONFIGURATION
CROSS SECTIONS
CYCLOTRON FREQUENCY
CYCLOTRON RADIATION
CYLINDERS
DENSITY
DISTRIBUTION
ELECTROMAGNETIC FIELDS
ELECTRONS
ENERGY
EXCITATION
FREQUENCY
GASES
HELIUM
HYDROGEN
INERT GASES
INTERACTIONS
IONIZATION
IONS
KEV RANGE
KRYPTON
MAGNETIC FIELDS
MEASURED VALUES
MOLECULES
NEON
NITROGEN
NUMERICALS
OSCILLATIONS
OXYGEN
PLASMA
PLASMA WAVES
PROTONS
RESONANCE
ROTATION
TEMPERATURE
XENON