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Volume 15 (1965)
- Issue 6 Pages 637-
- Issue 5 Pages 523-
- Issue 4 Pages 306-
- Issue 3 Pages 157-
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 15, Issue 4
Displaying 1-9 of 9 articles from this issue
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K. Minami, S. Takeda1965 Volume 15 Issue 4 Pages 306-339
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSThe absorption, reflection and transmission of microwaves by plasma slabs with ma, magnetic fields are calculated for the assumption that the collision damping is only the power dissipating mechanism. The solution of Maxwell equations for electromagnetic wave propagation is derived as a boundary value problem and numerically computed for various plasma parameters, magnetic fields and the slabthickness. It is of interest that the maximum absorptions appear. not only in the vicinity of the hybrid resonance but of the cut off points for uniform plasma slabs ticker than a wave length in free space and the conditions of maximum absorption somewhat deviate from the resonance or cut off. Such maximum absorptions can not be easily expected from Allis diagram which is valid only for an infinite collisionless plasma.
Such absorption pattern is also useful for estimating the electron temperature from the microwave power emitted from the plasmas, since the absorptivity is related to the emissivity.
Moreover, an example of a plasma slab with non uniformly distributed electrons is also computed by directly solving wave ecivations.View full abstractDownload PDF (1745K) -
Kozo Ando, Kazuo Mori, Eiji Yabe1965 Volume 15 Issue 4 Pages 340-351
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSThe intensities of the neutral helium spectral, lines emitted from helium plasma produced by the energetic arc have been measured, and the population densities of the energy levels of neutral heliumhave been calculated from them. Electron temperature could be deduced from them, since the distribution of the measured population densities above the. fifth principal quantum number was Maxwellian. Discharge conditions of helium arc were as folows; helium pressure at 10-2 torr, currents of 150, and 240 amp., and magnetic field. strength of 3540 gauss. In these cases the electron temperaturess of 0.19, 0.34, and 0, 34 ev respectively were obtained. It was considered from the radial intensity distribution of neutral helium lines that the measured electron temperatures were the values around the arc column.View full abstractDownload PDF (727K) -
Toshitaka Idehara, Yasushi Terumichi, Isao Takahashi, Kenji Mitani1965 Volume 15 Issue 4 Pages 352-364
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSIt is discussed that the cylindrical cavity of a reflection type, coaxial with a plasma column along the static magnetic field may amplify the incident wave. The Q-value contributed by the plasma (Qp) is calculated under the following conditions : i) The plasma is so tenuous that the perturbation theory is used.
ii) The velocity distribution function of plasma electrons is as follows : f° (v) ∝ vq exp (-bys).iii) The effective collision frequency for momentum transfer is dominantly due to the collision of electron with neutral particles and varies with the speed v as νc (v) ∝vh.
iV) The radius of the plasma is sufficiently smaller than the radius of the cavity.
In the case of Qp>0, the incident wave is always attenuated by the plasma-cavity system. However, when Qp<0, the plasma-cavity system has a possibility of amplification or oscillation. This Characteristic of the plasma-cavity system depends sensibly on the velocity distribution function of plasma electrons.View full abstractDownload PDF (1670K) -
Hiroshi Enjoji1965 Volume 15 Issue 4 Pages 385-412
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSA hot plasma produced by a large capacity condenser bank, the capacity and working voltage of which are 1.1 x 104μF and 500 volts, res-oectively, has been stabilized by strong alternating magnenic fields produced by condenser discharge through the external coil. In this case, the linear discharge current is interrupted steeply at the wave tail near the transition point between the first and the second half cycle of the magnetic field. The rate of decay of the currents at the interrupted point is of the order of 107 to 108 amp/sec. This interruption is caused by the magnetic fields of cusp geometry which are composed of the external magnetic field and those produced by the induced eddy currents in the electrodes. This mechanism of interruption of large currents is considered to be of importance to a kind of the controlling switches for high temperature plasma devices, as well as to the fast recovery of insulation of vacuum switches.View full abstractDownload PDF (2184K) -
Nobuki Kawashima1965 Volume 15 Issue 4 Pages 413-419
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSDouble probe characteristics in a streaming plasma from a plasma gun are investigated experimentally. When the probe is set parallel to the plasma stream, the plasma density around the leeward electrode is diminished in the shade of the windward electrode, and the double probe characteristic is asymmetric. The decrease of the ion saturation current for the leeward electrode is determined by the ion temperature in the plasma stream, when the plasma stream is collision-free. This method can also be applied to the ion temperature determination in the ionosphere or upper spaces by space probes.View full abstractDownload PDF (481K) -
Toshitaka Idehara, Haruhiko Abe, Hiroshi Kubo1965 Volume 15 Issue 4 Pages 420-424
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSWe have studied microwave radiation from a plasma column inthe region of ωc /ω>1 and ωp /ω<1, and have found that it exhibits the structure consisting of many lines as a function of static magnetic field. In this paper, the characteristics of these lines are shown. And then, as one possible explanation for them, the standing waves in a bounded plasma column are considered.View full abstractDownload PDF (627K) -
[in Japanese]1965 Volume 15 Issue 4 Pages 431-435
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSDownload PDF (553K) -
Sin-Li Chen1965 Volume 15 Issue 4 Pages 436-450
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSThe instantaneous direct display system of plasma parameters by means of Triple-Probe cited before, (2) naeds one of the three probes, say probe 2, always be forced at the floating potential in order to obtain the condition I2=O. (I2 : the current flowing into the probe 2). And so, for measurement of voltage difference Vd2, an unit with the impedance Z (or resistance Rfor statlionary cases) = ∞ is required, otherwise the condition of I2=O will be violated. In reality, however, this condition mentioned above is rather difficult to be realized technically, and a small current may be flowing into the probe 2 which should be floated, thus may give rise to some errors in the results of the measurement made.
In this paper, the case of the Direct Display System utilizing a “Non-Floating”, triple probe has been discussed, and the probe current as well as the voltage difference between the probes, which will bemeasured for determination of electron temperature Te and electron density Ne are calculated as the function of R, for stationary cases. So that, it is possible to dete-mine Te and Ne even when R≠∞.
The percentage errors of Te and Ne measured by means of the usual direct display system, in which the condition R≠∞ is assumed, are also discussed for various kinds of plasmas to be measured, under changing of R.View full abstractDownload PDF (1217K) -
I. HAYASHI, Y. SENO, T. KASHIWARA1965 Volume 15 Issue 4 Pages 451
Published: 1965
Released on J-STAGE: March 04, 2011
JOURNAL FREE ACCESSDownload PDF (562K)
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