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.

RAYONNEMENT FORTEMENT ACCRU PRÉSENTÉ PAR UNE ANTENNE ENROBÉE D'UNE GAINE DIÉLECTRIQUE ET D'UNE COUCHE DE PLASMA

1967 ◽  
Vol 45 (10) ◽  
pp. 3367-3380
Author(s):  
A. M. Messiaen ◽  
P. E. Vandenplas
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Dielectric Layer ◽  
Essential Role ◽  
Plasma Layer ◽  
Plasma Sheath ◽  
Operating Frequency

The plasma sheath existing between an antenna and a surrounding plasma layer plays an essential role. It is predicted that, for a given operating frequency, there exist certain plasma densities for which the system is resonant, and this very strongly enhanced radiation is fully confirmed by experiments. This combination of dielectric layer and plasma enables to tune an antenna even when its dimensions are much smaller than the vacuum wavelength. The influence of a static magnetic field is discussed.The same system can also be used as a frequency-sensitive receiving aerial.

scholarly journals Formation of an elongated plasma column by a magnetic confinement of a laser-produced plasma

1992 ◽  
Vol 10 (4) ◽  
pp. 767-776 ◽  
Author(s):  
T. Pisarczyk ◽  
A. Faryński ◽  
H. Fiedorowicz ◽  
P. Gogolewski ◽  
M. Kuśnierz ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Laser Plasma ◽  
Plasma Column ◽  
Target Region ◽  
X Ray ◽  
Laser Probing ◽  
Single Turn ◽  
Magnetic Coils ◽  
The Magnetic Field ◽  
Uniform Plasma

In this article, we present the formation of an elongated plasma column by combining a laser plasma with an external magnetic field. The laser plasma is produced by irradiating solid targets with a focused Nd-glass laser. The targets were placed on the axis of the two, single-turn magnetic coils, which provided a magnetic field up to 500 kg in the target region. The expanding laser plasma is confined by the magnetic field and an elongated and uniform plasma column is formed on the axis of the coils. The plasma column emits strong, soft X-ray radiation. The pinhole photographs show that the plasma column is at least 5 mm long. To study the interaction of the expanding laser plasma with a magnetic field, the laser probing diagnostic was used.

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.

ELECTROMAGNETIC RADIATION FROM AN ARBITRARY SLOT ON A CONDUCTING CYLINDER COATED WITH A UNIFORM COLD PLASMA SHEATH WITH AN AXIAL STATIC MAGNETIC FIELD

1964 ◽  
Vol 42 (7) ◽  
pp. 1369-1381 ◽  
Author(s):  
C. Yeh
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Cold Plasma ◽  
Considerable Effect ◽  
Plasma Sheath ◽  
Slot Antenna ◽  
Radiation Patterns ◽  
Conducting Cylinder ◽  
Slotted Antenna ◽  
Axial Static Magnetic Field

The expressions for the radiated fields of an arbitrary slot on a conducting cylinder coated with a cold plasma sheath with an axial static magnetic field are obtained. It is well known from the plane-wave analysis that the presence of a static magnetic field has a considerable effect on the transmission characteristics of the signal through the plasma sheath. The principal concern of this paper is to consider the effects of a static magnetic field on the radiation pattern of a plasma-coated slot antenna. Extensive numerical computations are carried out for the special case of an infinite axial slot. It is found that, if the plasma frequency is moderate, a small axial static magnetic field could change significantly the radiation patterns of the slotted antenna. Furthermore, owing to the anisotropy of the plasma medium, the radiation patterns are asymmetric.

RADIATION FROM A STRIP OF ELECTRIC CURRENT IN A MAGNETOIONIC MEDIUM

1967 ◽  
Vol 45 (5) ◽  
pp. 1675-1691
Author(s):  
A. D. Wunsch
Keyword(s):  
Magnetic Field ◽  
Resonance Frequency ◽  
Electric Current ◽  
Static Magnetic Field ◽  
Radiation Resistance ◽  
Finite Width ◽  
Hybrid Resonance ◽  
Wide Range ◽  
Field Integral ◽  
A Current

The radiation resistance of a strip of electric current immersed in a cold magnetoplasma is investigated. The current is assumed to flow in a direction perpendicular to the static magnetic field. Integral expressions are obtained for the radiation resistance of a Hertzian dipole and for a current strip of finite width and length. Numerical results covering a wide range of frequencies are presented for both of the sources. It is shown that there are two frequency ranges where the radiation resistance of the Hertzian dipole is infinite, while the radiation resistance of the strip is finite everywhere except at the upper hybrid resonance frequency. The way in which the length of the strip influences its radiation resistance is discussed.

scholarly journals Magneto-acoustic resonance in a non-uniform current carrying plasma column

1971 ◽  
Vol 6 (3) ◽  
pp. 607-614 ◽  
Author(s):  
J. Vaclavik
Keyword(s):  
Magnetic Field ◽  
Plasma Column ◽  
Mass Density ◽  
Acoustic Resonance ◽  
Acoustic Oscillations ◽  
Resonant Character ◽  
Uniform Current ◽  
Oscillating Magnetic Field ◽  
Uniform Plasma

The forced radial magneto-acoustic oscillations in a plasma column with nonuniform mass density and temperature are investigated. It turns out that the oscillations have a resonant character similar to that of the magneto-acoustic oscillations in a uniform plasma column. The properties of the axial and azimuthal components of the oscillating magnetic field are discussed in detail.

Decreased chemotaxis of human peripheral phagocytes exposed to a strong static magnetic field

2004 ◽  
Vol 91 (1) ◽  
pp. 59-65 ◽  
Author(s):  
S Sipka ◽  
I Szöllősi ◽  
Gy Batta ◽  
Gy Szegedi ◽  
Á Illés ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field

Intense Static Magnetic Field Induced Bone Growth in Vivo

1984 ◽  
Vol 3 (1) ◽  
pp. 223-234
Author(s):  
Frank Papatheofanis ◽  
Bill Fapatheofanls ◽  
Robert Ray
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Bone Growth
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