External Magnetization Research Articles

Electromagnetic Microinstabilities of Plasmas in a Uniform Magnetic Induction

Electromagnetic instabilities associated with transverse plasma waves propagating perpendicular to an external uniform magnetic induction B0 are investigated for a two-temperature Maxwellian distribution function. The analysis shows that no instability develops if V‖e2 < V⊥e2 where V‖e2 and V⊥e2 are the electron temperatures parallel and perpendicular to B0. For V‖e2 > V⊥e2 an instability develops if ωce2/ωpe2 < V‖e2/c2 [1 − (32)12 (V⊥e/V‖e)] where ωce and ωpe are the cyclotron and plasma frequency, respectively, and c is the velocity of light. The allowable frequency regions for this type of electromagnetic wave to exist across B0 are studied. It is found that below the plasma frequency there is always a narrow allowable frequency band just below any harmonics of the ion or electron cyclotron frequencies. Each width of the allowable frequency band is calculated.

Multicomponent Beam-Plasma Waves

The linearization procedure is applied to the equations governing a beam-plasma system, in which the stream velocities and the wavevector are parallel to the external magnetic induction. No special constraints are imposed on the parameters characterizing the constituent fluids in the equilibrium state of this macroscopic picture. From the MAXWELL equations an expression for the electromagnetic field of the wave is obtained and substituted in the equations of motion. The components of the first-order pressure tensors are computed in the low-temperature approximation, but without recurring to the strong magnetic induction CGL hypothesis. Since the equations of motion are now expressed only in the components of the perturbations of the drift velocities, the dispersion relations follow immediately. These relations are applicable to all beam-plasma systems comprised between the now conventional multicomponent plasma and the system of beams of charged particles. Some known cold beam-plasma cases are included in the general dispersion equations.