Artificial production of broadband VLF hiss by means of Cerenkov radiation process as side effect of electron accelerator aurora generating experiment

Artificial production of VLF hiss

For certain values of parameters, a point charge moving with uniform velocity parallel to the magnetostatic field in an unbounded magnetoionic medium excites two modes. In a recent investigation, Kurdyumov has concluded that of these two modes, one is associated with emission of energy and the other with absorption. Theoretical arguments as well as experimental evidence are advanced in order to establish that both the modes, contrary to the conclusion of Kurdyumov, are associated with emission of energy.

Cerenkov radiation in a magnetoionic medium

The utilization of refractive index surfaces in conjunction with the Clemmow, Mullaly, Allis (CMA) diagram greatly simplifies the determination of the regions of Cerenkov radiation and the types of waves emitted in a cold, collisionless, electron magnetoplasma Also, the physical insight gained by this approach is used to explain the qualitative behavior of the power spectrum

Utilization of the Refractive Index Surfaces to Evaluate Cerenkov Radiation in an Infinite Magnetoplasma

The radiation from a moving point charge in an anisotropic cold plasma drifting uniformly along a finite external magnetic field is investigated. It is assumed that the charge is moving uniformly in the direction of the external magnetic field. In general, the radiation consists of two waves, i.e., the ordinary and extraordinary waves. The effects of the drift motion of the background plasma on the radiation characteristics of both waves are discussed in detail. It is found that as the drift velocity of the plasma increases and approaches that of the moving source, the radiated energy of the ordinary wave is resonantly enhanced and the Cerenkov ray becomes concentrated in the direction of the motion of the source.

Radiation from a moving point charge in a drifting anisotropic plasma

Wave excitation by using electron beam antennas is planned in the Space Experiments With Particle Accelerators project. This paper discusses the radiation of electromagnetic waves from a density-modulated electron beam antenna injected along the earth magnetic field into the ionosphere. Strong radiation at the lower hybrid frequency ƒLHR and the higher frequency band (ƒLHR <ƒ ≤ ƒHe/2, where ƒ and ƒHe are frequency and electron cyclotron frequency, respectively) is predicted theoretically for an appropriate beam velocity.

Radiation of electromagnetic waves from an electron beam antenna in an ionosphere

The radiation from a point charge moving uniformly in a plasma is investigated when the charge is moving in the direction of an external magnetic field. In general, there are two modes, for each of which all the components of the electric and magnetic field are present. The two parameters of interest in this problem are the ratio of the velocity of the charges to the free-space velocity of electromagnetic waves, and the ratio of the gyromagnetic frequency to the plasma frequency of the electrons. For two sets of values of these parameters, the frequency and the angular spectrum of the emitted radiation are obtained. In certain cases, as many as three Cherenkov rays are found to propagate in the same direction; these multiple-rays, however, correspond to different frequency components and to different modes of propagation. The motivation for this investigation is indicated briefly. (auth)

H.S. Tuan

Papers

RADIATION FROM A UNIFORMLY MOVING CHARGE IN AN ANISOTROPIC PLASMA. Technical Report No. 389