RADIATION FROM AN ELECTRIC DIPOLE IN AN AXIALLY MAGNETIZED PLASMA COLUMN—DIPOLAR MODES

1967 ◽  
Vol 45 (11) ◽  
pp. 3627-3648 ◽  
Author(s):  
G. L. Yip ◽  
S. R. Seshadri
Keyword(s):  
Electric Dipole ◽  
Radiation Resistance ◽  
Guided Waves ◽  
Plasma Frequency ◽  
Axial Magnetic Field ◽  
Radiation Power ◽  
Magnetized Plasma ◽  
Signal Frequency ◽  
Radiation Characteristics ◽  
Power Pattern

The radiation characteristics of an electric dipole are investigated for the case in which it is situated on, and oriented perpendicular to, the axis of an infinitely long and axially magnetized column of uniform, lossless, and cold plasma. In general, the electric dipole will excite space waves as well as guided waves, both of which are dipolar in nature. The radiation power pattern and the radiation resistance, resulting from the space waves, are investigated as a function of the column radius, the signal frequency, and the strength of magnetization. For thin and isotropic plasma columns, the radiation resistance has a maximum, which is due to the dipolar resonance. This resonance occurs at 1/√2 times the plasma frequency. The introduction of anisotropy by the application of an axial magnetic field results in the splitting of the single dipolar resonance into two, occurring at frequencies below and above 1/√2 times the plasma frequency. Finally, a comparison is made between the radiation characteristics in the present problem and those due to an axially oriented dipole.

The Excitation of Resonances by a Dipole Antenna Inside a Hollow Cylindrical Plasma

1972 ◽  
Vol 50 (21) ◽  
pp. 2628-2637 ◽  
Author(s):  
G. L. Yip
Keyword(s):  
Electric Dipole ◽  
Radiation Resistance ◽  
Collision Frequency ◽  
Plasma Frequency ◽  
Dipole Antenna ◽  
Signal Frequency ◽  
Cylindrical Plasma ◽  
Point Electric Dipole ◽  
Practical Implications ◽  
Plasma Tube

The problem of the excitation of resonances by a dipole antenna inside a hollow cylindrical plasma is examined. The plasma is assumed to be cold, uniform, isotropic, and lossy. A transversely oriented point electric dipole antenna lying on the axis of the cylindrical plasma is the source under consideration. For a thin and lossless plasma, resonances are found to occur at the two frequencies corresponding to dipolar resonances in a hollow cylindrical plasma as derived earlier by, for example, Kaiser and Closs, and Vandenplas. In addition, there is also an antiresonance at the plasma frequency. The radiation resistance and radiation patterns of the plasma-covered dipole are presented to show the effects of the radii of the plasma tube, the signal frequency and the collision frequency. The possible practical implications of the present study as pertaining to the improvements of reentry communication and the excitation of plasma resonances in ionospheric irregularities are discussed.

EFFECT OF STATIC MAGNETIC FIELD ON RADIATION THROUGH A PLASMA SHEATH

1966 ◽  
Vol 44 (9) ◽  
pp. 1941-1964 ◽  
Author(s):  
S. R. Seshadri ◽  
G. L. Yip
Keyword(s):  
Magnetic Field ◽  
Radiation Pattern ◽  
Static Magnetic Field ◽  
Radiation Resistance ◽  
Plasma Column ◽  
Guided Waves ◽  
Plasma Sheath ◽  
Radiation Characteristics ◽  
Current Filament ◽  
Uniform Plasma

The radiation characteristics of a filament of finite length with a triangular current distribution are investigated for the case in which it is situated along the axis of an infinitely long, axially magnetized column of uniform plasma. In general, the current filament will excite guided waves along the plasma column as well as space waves. The radiation pattern in the far zone and the radiation resistance of the current filament contributed by the space waves are studied as a function of the radius of the plasma column, the operating frequency of the source, the strength of the applied static magnetic field, and the length of the current filament with the current at its center kept constant. In particular, for various frequencies below the plasma frequency and for a particular radius of the plasma column, the radiation pattern and the radiation resistance are presented as a function of the strength of the applied static magnetic field. These results indicate that a significant improvement in the transmission through a plasma sheath can be obtained by a suitable application of a static magnetic field. A brief discussion of the characteristics of the possible guided waves along the plasma column is also included.

scholarly journals Spherical Helices for Resonant Wireless Power Transfer

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Maja Škiljo ◽  
Zoran Blažević
Keyword(s):  
Radiation Resistance ◽  
Power Transmission ◽  
Wireless Power Transfer ◽  
Antenna Design ◽  
Impedance Match ◽  
Wireless Power ◽  
Radiation Characteristics ◽  
Antenna Size ◽  
Helical Antennas ◽  
Theoretical Considerations

The capabilities of electrically small spherical helical antennas for wireless power transmission at small and moderate distances are analyzed. Influence of design on antenna radiation resistance, efficiency, and mode ratio is examined. These are the factors that, according to the theoretical considerations depicted herein, govern the maximum transfer performances. Various designs and configurations are considered for the purpose, with accent on small-size receivers suitable for implementation in powering common-sized gadgets. It is shown that spherical helix design is easily manipulated to achieve a reduced antenna size. Good radiation characteristics and impedance match are maintained by multiple-arm folded antenna design and by adjusting the separation between the arms.

Synchrotron radiation from single electrons gyrating in a magnetoactive plasma

1969 ◽  
Vol 47 (7) ◽  
pp. 757-768 ◽  
Author(s):  
P. C. W. Fung
Keyword(s):  
Synchrotron Radiation ◽  
Plasma Frequency ◽  
Radiation Power ◽  
Magnetoactive Plasma ◽  
Electron Plasma ◽  
Relativistic Electrons ◽  
Relative Importance ◽  
Numerical Examples ◽  
The Past ◽  
Single Electrons

In this paper, the incoherent synchrotron radiation power emitted by relativistic electrons gyrating in a cold magnetoactive plasma is rederived, correcting errors which have occurred in the past literature. One can specify the background plasma by the quantity A = ωp2/ωH2 (ωp is the angular electron plasma frequency and ωH is the angular electron gyro-frequency), i.e. the relative importance of the plasma frequency to the gyro-frequency. The general spectral features of synchrotron radiation from single electrons radiating in plasmas of large [Formula: see text] and small [Formula: see text] are discussed with the aid of a number of numerical examples.

Radiation Power of a High-Current Vacuum Arc Stabilized by an Axial Magnetic Field in the Visible and UV Ranges of the Spectrum

2021 ◽  
Vol 47 (2) ◽  
pp. 118-121
Author(s):  
Yu. A. Barinov ◽  
K. K. Zabello ◽  
A. A. Logachev ◽  
I. N. Poluyanova ◽  
E. V. Sherstnev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Radiation Power ◽  
Vacuum Arc ◽  
High Current

RADIATION FROM A LINE SOURCE IN A UNIAXIALLY ANISOTROPIC PLASMA

1963 ◽  
Vol 41 (2) ◽  
pp. 246-257 ◽  
Author(s):  
H. S. Tuan ◽  
S. R. Seshadri
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Line Source ◽  
Plasma Frequency ◽  
Angular Spectrum ◽  
Radiation Characteristics ◽  
Magnetic Current ◽  
Line Charge ◽  
Unit Path Length ◽  
Moving Line

Two problems of radiation in a magnetized, incompressible plasma are investigated. The radiation characteristics of a line source of magnetic current are studied for the case in which the external magnetic field is infinite and oriented in a direction perpendicular to that of the source. The second problem that is treated is the radiation from a uniformly moving line charge. Two cases are considered, namely: (1) when the motion of the line charge is parallel and (2) when it is perpendicular to the direction of the external magnetic field. In each case it is found that there is a Cerenkov-type radiation for frequencies less than the plasma frequency. The frequency and the angular spectrum, as well as the total energy radiated per unit path length, are determined for both cases.

scholarly journals The K-shell radiation of a double gas puff z-pinch with an axial magnetic field

2003 ◽  
Vol 21 (2) ◽  
pp. 255-264 ◽  
Author(s):  
S.A. CHAIKOVSKY ◽  
A.Yu. LABETSKY ◽  
V.I. ORESHKIN ◽  
A.V. SHISHLOV ◽  
R.B. BAKSHT ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiation Source ◽  
Axial Magnetic Field ◽  
Radiation Power ◽  
Plasma Radiation ◽  
Radiation Hydrodynamics ◽  
One Dimensional ◽  
Z Pinch ◽  
Good Agreement

A double shell z-pinch with an axial magnetic field is considered as a K-shell plasma radiation source. One-dimensional radiation-hydrodynamics calculations performed suggest that this scheme holds promise for the production of the K-shell radiation of krypton (hν ≈ 12–17 keV). As a first step in verifying the advantages of this scheme, experiments have been performed to optimize a neon double-shell gas puff with an axial magnetic yield for the K-shell yield and power. The experiments show that the application of an axial magnetic field makes it possible to increase the K-shell radiation power and reduce the shot-to-shot spread in the K-shell yield. Comparisons between the experiments and modeling are made and show good agreement.

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