High-frequency waves in a magnetized plasma

1967 ◽  
Vol 1 (3) ◽  
pp. 289-304 ◽  
Author(s):  
D. E. Baldwin

Equations are derived which may be used to describe the propagation of electromagnetic waves in non-uniform magnetized plasma when the wave frequency is near the second electron cyclotron harmonic. The method used is to expand the linearized Vlasov equation in powers of the electron Larmor radius divided by a typical scale length. The general equations are then specialized to the problem of the coupling of transverse waves to the longitudinal modes (Bernstein modes) which exist when all quantities vary only in a plane perpendicular to a straight magnetic field. The form of these equations for two simple models of the equilibrium plasma is given. Comments are made about the equations for the higher harmonics, and the question of boundary conditions is discussed. Finally, the general equations are examined in the limit Ω→0 in order to provide equations suitable for the description of high frequency waves in non-magnetized plasmas.


1973 ◽  
Vol 10 (1) ◽  
pp. 1-12 ◽  
Author(s):  
J. Preinhaelter ◽  
V. Kopecký

Propagation of high-frequency electromagnetic waves in a weakly inhomogeneous magnetized plasma is investigated. We suppose the density gradient to be perpendicular to an external magnetic field, and the waves to be incident obliquely upon the plasma from vacuum. We find that the transmission coefficient of the ordinary wave through the plasma resonance is approximately equal to one in a fairly wide range of angles of incidence γ near the value γ0 = arcsin (Ωc/)(Ωo + Ω) ½. The transmitted ordinary wave is fully transformed into an extraordinary wave at higher densities. Then it propagates back to the region of a smaller density, and is fully transformed into the Bernstein modes in the vicinity of the hybrid resonance. Complications connected with the evanescent layer, which arise when the high-frequency energy is transmitted into the plasma in the form of the extraordinary wave, can thus be removed by using the ordinary wave with the angle of incidence chosen appropriately.


1988 ◽  
Vol 37 (3) ◽  
pp. 469-474 ◽  
Author(s):  
A Bahnsen ◽  
M Jespersen ◽  
E Ungstrup ◽  
R Pottelette ◽  
M Malingre ◽  
...  

1968 ◽  
Vol 46 (10) ◽  
pp. S638-S641 ◽  
Author(s):  
D. B. Melrose

The acceleration of ions from thermal velocities is analyzed to determine conditions under which heavy ions can be preferentially accelerated. Two accelerating mechanisms involving high-and low-frequency hydromagnetic waves respectively are considered. Preferential acceleration of heavy ions occurs for high-frequency waves if the frequency spectrum falls off faster than (frequency)−1. For the low-frequency waves heavy ions are less effectively accelerated than lighter ions. However, very heavy ions can be preferentially accelerated, the abundances of the very heavy ions being enhanced by a factor Ai over the thermal abundances. Acceleration of ions in the envelope of the Crab nebula is considered as an example.


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