Methods of determining the density and temperature distribution of a plasma using electromagnetic waves

Abstract

The authors consider a number of methods of determining the density and temperature distributions along the radius of a plasma cylinder. Determination of the electron density and temperature distributions by measuring the electron cyclotron damping or the phase of an electromagnetic wave passing in a straight line through a plasma cylinder as a function of the “sighting” distance. If the electron velocity distribution is not Maxwellian, additional measurements of the absorption or the phase as a function of the magnetic field or of the angle between the direction of the ray and the magnetic field enable one to find the electron velocity distribution function along the magnetic field at each point in the plasma cylinder. Determination of the plasma density distribution from the fraction of a microwave ray passing through a plasma in a direction perpendicular to the magnetic field, and determination of the effective collision frequency distribution from damping of the intensity of the refracted ray. Determination of the temperature of a plasma in a strong magnetic field from the measured frequency-dependence of the absorption of low-frequency electromagnetic waves under conditions of acoustic resonance.

Turbulence in Aqueous Glucose Solutions Induced by Magnetic Field

“…In the geometrical optics approximation, the differential equation for the trajectory of a microwave ray in a plasma cylinder (see Fig. 1) looks like [12,17]…”

“…The ray trajectory length in plasma depends on the entrance angle and the plasma parameters. In the case of cylindrical symmetry, the element of a ray path is determined as [12,17]…”

“…In plasma diagnostics, the methods that are based on the refraction of microwave rays in plasma [9][10][11][12][13][14][15][16][17][18] are also applied; they are classed to active microwave ones. In those methods, the dependences of the refraction angle on the plasma parameters at the plasma probing by an ordinary wave and on the magnetic field strength in the case of extraordinary wave are analyzed [17,18]. The application of the refraction allows the distribution of the plasma density to be determined.…”

Experimental Study of Inhomogeneous Reflex-Discharge Plasma Using Microwave Refraction Interferometry

“…It is worth noting that, in the course of interferometric measurements, the phase shift obtains an additional error owing to the refraction of microwave beams in a plasma [1][2][3][4][13][14][15][16]. Methods based on the microwave refraction in an inhomogeneous plasma are also applied to the plasma diagnostics [17][18][19][20][21][22]. In particular, the oblique probing of a plasma is carried out, and either the dependence of the refraction angle on the plasma parameters [17][18][19][20][21] or the phase shift [22], which is used to determine the average plasma density in the corresponding cross-section segment, is determined experimentally.…”

“…Methods based on the microwave refraction in an inhomogeneous plasma are also applied to the plasma diagnostics [17][18][19][20][21][22]. In particular, the oblique probing of a plasma is carried out, and either the dependence of the refraction angle on the plasma parameters [17][18][19][20][21] or the phase shift [22], which is used to determine the average plasma density in the corresponding cross-section segment, is determined experimentally. An important conditions for the applicability of those methods are the availability of narrow microwave beams and the validity of the geometric optics approximation.…”