Input Resistance of a Short Dipole Antenna in a Warm Uniaxial Plasma

Abstract

The input resistance of a short dipole antenna immersed in a warm magnetoplasma is calculated on the basis of the kinetic theory (Boltzmann equation). The plasma is uniaxial; i.e., the cyclotron frequency is much larger than the operating frequency of the antenna and the plasma frequency. The plasma is homogeneous, and collisions are included although the sheath is neglected. The dipole is assumed to be infinitesimally thin (producing an infinite input reactance( except for the case in which the dipole axis is parallel to the static magnetic field when we allow the dipole to have a nonzero radius and calculate the input impedance. It is found that at frequencies much less than the plasma frequency the input resistance differs markedly from the hydrodynamic and cold‐plasma results because of collisionless absorption processes. The input resistance is generally smaller when the dipole axis is inside the resonance cone than when it is outside. The resonance cone anomaly in the input resistance is reduced in magnitude from that of the cold‐plasma theory and is shifted to a higher frequency.