Radio frequency properties of a plane grid capacitor immersed in a hot collision-free plasma

1968 ◽  
Vol 2 (3) ◽  
pp. 339-351 ◽  
Author(s):  
R. Buckley
Keyword(s):  
Plasma Frequency ◽  
Real Component ◽  
Hot Plasma ◽  
Capacitive Component ◽  
Longitudinal Plasma ◽  
Imaginary Field ◽  
Complex Admittance ◽  
Frequency Properties ◽  
Plane Grid ◽  
Made In

A pair of plane parallel grids is inserted in a hot plasma, and an oscillatory voltage is applied across them. The electric field excited in the plasma, and the complex admittance of the grid/plasma system, are computed for applied frequencies high enough to justify neglect of ion response. The grids are electrically, but not mechanically, coupled to the plasma, which is assumed to be in a spatially uniform collision free Maxwellian equilibrium state. The field is computed as a function of distance from the grid plates over a range of frequencies covering the plasma frequency, and the complex admittance of the system is computed as a function of frequency at various grid separation distances. The real component of the field and the capacitive component of the admittance are subject to three major effects: cold plasma dielectric behaviour, oscillatory Debye sheaths on the grids, and (above the plasma frequency), longitudinal plasma waves. The imaginary field component and the conductive admittance component are produced by spatial Landau damping. In an accompanying paper (Freeston 1968), the computed admittance is compared with laboratory measurements made in a situation approximating well to the idealized problem considered here.

scholarly journals SolpeX: the soft X-ray flare polarimeter–spectrometer for the ISS

2014 ◽  
Vol 10 (S305) ◽  
pp. 114-120
Author(s):  
Janusz Sylwester ◽  
Stefan Płocieniak ◽  
Jarosław Bakała ◽  
Żaneta Szaforz ◽  
Marek Stȩślicki ◽  
...  
Keyword(s):  
Solar Flares ◽  
Line Emission ◽  
Impulsive Phase ◽  
Particle Beams ◽  
X Ray ◽  
Hot Plasma ◽  
Spectral Imager ◽  
Polarized Bremsstrahlung ◽  
Made In ◽  
Fast Rotating

AbstractWe present the innovative soft X-ray spectro-polarimeter, SolpeX. This instrument consists of three functionally independent blocks. They are to be included into the Russian instrument KORTES, to be mounted onboard the ISS. The three SolpeX units are: a simple pin-hole X-ray spectral imager, a polarimeter, and a fast-rotating drum multiple-flat-crystal Bragg spectrometer. Such a combination of measuring blocks will offer a new opportunity to reliably measure possible X-ray polarization and spectra of solar flares, in particular during the impulsive phase. Polarized Bremsstrahlung and line emission due to the presence of directed particle beams will be detected, and measurements of the velocities of evaporated hot plasma will be made. In this paper we discuss the details of the construction of the SolpeX units. The delivery of KORTES with SolpeX to the ISS is expected to happen in 2017/2018.

scholarly journals Electromagnetically induced transparency in plasma

2001 ◽  
Vol 19 (2) ◽  
pp. 175-179 ◽  
Author(s):  
B. ERSFELD ◽  
D.A. JAROSZYNSKI
Keyword(s):  
Electromagnetic Waves ◽  
Plasma Frequency ◽  
Electromagnetically Induced Transparency ◽  
Plane Waves ◽  
Electron Mass ◽  
Number Density ◽  
Relativistic Fluid ◽  
Longitudinal Plasma ◽  
Induced Transparency ◽  
The Waves

The coupled propagation of two electromagnetic waves in plasma is studied to establish the conditions for induced transparency. Induced transparency refers to the situation where both waves propagate unattenuated, although the frequency of one (or both) of them is below the plasma frequency so that it could not propagate in the absence of the other. The effect is due to the interaction of the waves through their beat, which modulates both the electron mass and, by exciting longitudinal plasma oscillations, their number density, and thus the plasma frequency. Starting from a relativistic fluid description, a dispersion relation for plane waves of weakly relativistic intensities is derived, which takes into account the polarization of the waves and the nonlinearities with respect to both their amplitudes. This serves as a basis for the exploration of the conditions for induced transparency and the modes of propagation.

On oscillating electric dipoles immersed in a hot plasma

1968 ◽  
Vol 2 (3) ◽  
pp. 437-448 ◽  
Author(s):  
S. R. Watson
Keyword(s):  
Magnetic Field ◽  
Distribution Function ◽  
Electric Fields ◽  
Plasma Frequency ◽  
Velocity Distribution Function ◽  
Electron Velocity ◽  
Electron Velocity Distribution ◽  
Electron Velocity Distribution Function ◽  
Hot Plasma ◽  
Electric Dipoles

In this paper the electric fields of an infinitesimal dipole oscillating in a hot plasma are derived in the absence of an external magnetic field; explicit expressions are obtained by making an approximation on the background electron velocity distribution function. These results are applied to investigate the resonance observed at the plasma frequency, and to estimate the radiation resistance of the dipole.

TEMPERATURE DEPENDENCE OF JOSEPHSON PLASMA MODES IN Bi2Sr2CaCu2O8+δ NEAR Tc

2000 ◽  
Vol 14 (05) ◽  
pp. 547-554
Author(s):  
KAZUO KADOWAKI ◽  
ITSUHIRO KAKEYA ◽  
TETSU WAKABAYASHI ◽  
RYO NAKAMURA ◽  
SABURO TAKAHASHI
Keyword(s):  
Plasma Frequency ◽  
Fluid Model ◽  
Microwave Frequency ◽  
Tunneling Probability ◽  
Temperature Dependent ◽  
Plasma Energy ◽  
Longitudinal Plasma ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Josephson Plasma

A strong temperature dependent phenomenon of the Josephson plasma resonance mode has been found in high-Tc superconductor Bi 2 Sr 2 CaCu 2 O 8+δ in a microwave frequency region between 9 and 50 GHz. The longitudinal plasma frequency sharply decreases and disappears just below Tc. The extrapolated plasma energy is estimated to be ℏω p (0)=2.59× 10-4 eV . Since the plasma frequency, ω p , is determined by the Anderson-Higgs–Kibble mechanism and it is expected to be temperature independent, this phenomenon can not be accounted for by the conventional underst and ing of the plasma mode in superconductors. Experimental results are discussed in terms of the two fluid model, in which the intrinsic Josephson nature of the coupling restricting the tunneling probability of quasiparticles between layers is considered to be as a dumping mechanism of the quasiparticles in this system.

scholarly journals Interacting Intersecting Masers

1994 ◽  
Vol 140 ◽  
pp. 372-373
Author(s):  
Shuji Deguchi
Keyword(s):  
Raman Scattering ◽  
Wave Vector ◽  
Stimulate Raman Scattering ◽  
Plasma Frequency ◽  
Stimulated Raman Scattering ◽  
The Other ◽  
Longitudinal Waves ◽  
Longitudinal Plasma ◽  
Water Masers ◽  
Scale Length

An interaction of two masers through plasma longitudinal waves in the Stimulate Raman Scattering has been investigated and applied for the extreme high-velocity (900 km s-1) water masers discovered in NGC 4258. For the stimulated Raman scattering, the frequency down-shifted components are easily created but not the up-shifted components. We use the interacting masers for the explanation for the presence of the up-shifted components. The interaction occurs when the wave vector of the longitudinal plasma wave associated with one incident maser coincides with the wave vector of the other longitudinal wave associated with the other maser. This interaction produces two daughter waves, frequency up-shifted and down-shifted radiations with a shift of roughly a plasma frequency. This interaction occurs when two masers intersect with intersecting angle of about 176 degree in plasma of the electron density of about 5 106 cm-3. The brightness temperature of the original incident masers must be greater than about 1013 K (depending on the line width, and the maser beaming angle, etc.) and the scale length of plasma must be larger than about 1013 cm.

scholarly journals THE ELECTRICAL PROPERTIES OF SYNTHETIC MEMBRANES

1949 ◽  
Vol 32 (4) ◽  
pp. 453-460 ◽  
Author(s):  
Wilhelm S. Albrink ◽  
Raymond M. Fuoss
Keyword(s):  
Electrical Properties ◽  
Electrical Behavior ◽  
Electrical Measurements ◽  
Butyl Bromide ◽  
Real Component ◽  
Electrolytic Conductance ◽  
Circular Arc ◽  
Synthetic Membranes ◽  
Flexible Films ◽  
Complex Admittance

By the addition of n-butyl bromide to a 1:19 copolymer of 4-vinylpyridine and styrene, water-insoluble, strong polyelectrolytes can be prepared. The addition of a hydrocarbon plasticizer permits the casting of flexible films in which large polycations are immobilized but in which bromide ions (or other small anions) are free to move. Electrical measurements on these membranes showed that they could be represented by a complex admittance: an electrolytic conductance in parallel with a pure A. C. impedance. The latter gives a circular arc when real component is plotted against imaginary. These synthetic membranes thus resemble in their electrical behavior that found by Cole for a variety of biological membranes.

scholarly journals Harmonics in the Spectra of Solar Radio Disturbances

1954 ◽  
Vol 7 (3) ◽  
pp. 439 ◽  
Author(s):  
JP Wild ◽  
JD Murray ◽  
WC Rowe
Keyword(s):  
Standard Model ◽  
Fundamental Frequency ◽  
Solar Radio ◽  
Plasma Frequency ◽  
Preliminary Investigation ◽  
Charged Particles ◽  
Frequency Separation ◽  
Spectral Features ◽  
Plasma Oscillations ◽  
Longitudinal Plasma

The paper describes observations with a 40-240 McJs radio spectroscope leading to the discovery and preliminary investigation of harmonics in the spectra of sporadic bursts from the SWl. It is found that spectral features of bursts are commonly duplicated with a 2: 1 frequency separation. The ratio is sometimes appreciably lower though apparently never greater. This and other features of the spectra are shown to support the hypothesis that the fundamental frequency corresponds to the natural plasma frequency of the corona in the vicinity of the source. By applying this result to a standard model of the corona, information on the position, velocity, and size of the sources is deduced. The results suggest that the generation of bursts may be associated with longitudinal plasma oscillations excited by fast streams of charged particles.

scholarly journals Magnetfeldmessungen mit Hilfe des Zeeman-Effektes

1964 ◽  
Vol 19 (9) ◽  
pp. 1111-1120
Author(s):  
Klaus Hübner
Keyword(s):  
Line Profile ◽  
Zeeman Effect ◽  
Line Emission ◽  
Homogeneous Magnetic Field ◽  
Mean Value ◽  
Time Variable ◽  
Hot Plasma ◽  
Time Variations ◽  
Inhomogeneous Line ◽  
Made In

A method for the measurement of time-variable magnetic fields from the ZEEMAN effect of timevariable line emission is described. This method is independent of the special line profile and of time variations in intensity, line profile and line shift. The sensitivity of the method and the accuracy of the measurement are discussed. Test measurements were made in a nitrogen discharge with an external homogeneous magnetic field having 130 kc/sec frequency. — The measurement of inhomogeneous fields from spatial inhomogeneous line emission gives a mean value of the field which depends on the spatial distribution of the line emission. Nevertheless, measurements made on a little fast Θ-pinch with a N II line, which was emitted from the hot plasma, were reproduceable.

Wechselwirkung von Ionen- und Elektronenwellen mit intensitätsgleicher Emission bei der einfachen und doppelten Plasmafrequenz

1971 ◽  
Vol 26 (11) ◽  
pp. 1909-1918
Author(s):  
D. Beermann
Keyword(s):  
Plasma Frequency ◽  
Plasma Waves ◽  
Type Ii ◽  
Flux Intensity ◽  
Order Of Magnitude ◽  
Solar Type ◽  
Longitudinal Plasma ◽  
Two Fluid ◽  
Two Fluid Plasma ◽  
Burst Emission

Nonlinear interaction of longitudinal plasma waves in two-fluid plasma exciting the solar type II burst emission is investigated. The interaction of ion and electron waves yields radiation at the fundamental plasma frequency, while emission at twice the plasma frequency is caused by self-interaction of the electron waves. Equal flux intensity results in both the radiation bands if the variation of electron density associated with the two wave modes is of the same order of magnitude.

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