This paper treats Cerenkov radiation produced by a charged particle or beam moving in a plasma along an arbitrary direction with respect to the magnetic field. The expressions for the Cerenkov condition and the radiation output are obtained for the cases of a charged particle or beam moving both along and perpendicular to the magnetic field. The frequency ranges of the radiation for two type of waves, i.e. the ordinary and extraordinary waves, are determined by using the Cerenkov condition.
For the case of a charged particle of beam moving in a plasma along the magnetic field, the extraordinary waves can be emitted, for a certain range of β=v/c, in the range of frequencies lower as wellas higher than the plasma frequency, and then the regions for the ordinary, and extraordinary waves can overlap. Under the non-relativistic condition (β<<1), the total power radiated by a charged particle or a bunched beam is, respectively, as follows :
[dW/dt] _??_β_??_0μ₀q²v/16π (2ω²_p+ω²_c)
or
[W] _??_β_??_0μ₀I²/8·ω³/ω²_C, ω_p≤ω<√ω²_p+ω²_c,
where μ₀ is the permeability in vacuum, ω_p and ω_c are the plasma and cyclotron angular frequencies, q and v are the charge and velocity of a particle, and I is the beam current. The power output for the extraordinary waves is evaluated numerically. The result shows that Cerenkov radiation occurs with considerably high power at comparatively small magnetic field strengths and also under non-relativistic conditions.
For the case of a charged particle or beam moving perpendicular to the magnetic field, the ordinary waves are emitted in the range of frequencies higher as well as lower than the plasma frequency, while the extra-ordinary waves are emitted in the range of frequencies higher than the plasma frequency. The maximum frequency emitted for both types of waves never exceed the frequency defined by ω=√ω²_p+ω²_c·In the non-relativistic case (β<<1) only the ordinary waves are emitted under the following coherence condition :
[cos²θ₀ (φ)] β_??_0=1-ω² (ω²_p+ω²_c-ω²) /ω²_pω²_csin²φ, φ≠0,
and the frequency ranges are separated into two regions. The radiation pattern is more complicated as compared with the case of a particle or beam moving along the magnetic field; instead of circular cones, we have two non-circular Cerenkov cones for the ordinary and extraordinary waves, with the radiation intensity varying on different generatrices of these conical surfaces.

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The Cerenkov radiation per unit time from a uniformly moving charged particle (with the electron charge q) in a magnetoplasma is calculated to be
(q²ω₀2/2ν) ln (ν²/ω₀²_??__m²)
under the assumptions (1) the gyration frequency of the plasma electrons is much larger than the collision frequency, and (2) the particle velocity v is nonrelativistic but 1n (v²/ω₀²_??__m²) >>1. Here ω₀ is the plasma frequency, _??__m the limiting length for the treatment of the plasma as a continuous medium, i.e., the mean distance between the electrons.

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The electron density of the low pies sureplasma was measured with a microwave interferometer bridge and with Langmuir probes simultaneously.At lower electron densities (ca.5×10¹⁰/cc), the density obtained from microwave phase shift was lager than that obtained from Langmuir probe possibly due to some inherent error in positive probe measurements.
At higher density, however, the agreement between both densities is fairly good if suitable considerations are paid for microwave horn-plasma coupling.
Extremely small horn to plasma distance in microwave measurement gives improperly large phase shift or large apparent electron density possibly due to multiple reflections of the incident microwave. Collision frequency of electron was also obtained from microwave attenuation measurements by interferometer.
The electron temperature was given from Langmuir probe characteristics by usual method. From these two measurements, collision cross section of Argon for electron was calalated.

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The temperature relaxation in a fully ioniyad plasma is discussed, which consists of electrons and one kind of positive ions.
The dynamical behaviour of a test ion is trested as a Brownion motion, where the swall-angle collisions only are considered. The relaxation time between ion and electron-temperatures has been calculated, which reads
3/16√πe⁴ m₁m₂/n₁+n₂ (kT₁/m₁+kT₂/m₂) ^3/2 [log (λbkwax)] ^-1,
Where -e is the electonic charge, m the mass, n the number deusity, λ_D the Debye length, and kmax the inverse mean distance between electrons and ions.
It is worth to notice that the result is completely symmetric about the electron and the ion, although the effect of large-angle collisions has not been taken into accounts.

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The ambipolar diffusion column in a transverse magnetic field is treated with phenomenological theory. In the transverse magnetic field, the cross section of plasma column is a ellipse whose major axis is parallel to the magnetic field. The spatial distributions of electron density and current density are symmetry in regard to the minor axis and are asymmetry in regard to the major axis. For example, the distributions of electron density, current density and charge density on the minor axis are shown in Fig. 2, Fig. 3, and Fig. 5 respectively. In section 5, the equation of the internal energy is given and the electron temperature is determined.In sections 4 and 5, such behaviors of plasma column as movement of column, current-voltage characteristic and the relation between longitudinal electric field and transverse magnetic field are discussed.

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