- oo) are shown in Fig. 30. We note that for the cyclotron-inactive r modes the form of the w versus q curve is similar to that for the plasma in the absence of a magnetic field (Fig.
U=-1 k Fig. 9. Combined (cyclotron plus spin-flipping) transitions of a free electron in a magnetic field. 16 qzf2kz E. Burstein ~ I) takes the form LIW = liw(q) = (LIL + Llam*gf2m)liwe = liqvp(l, a) cos() (29) Apart from selection rules and the magnitudes of Ll W the same considerations that apply for cyclotron and spin excitations also apply to the combined cyclotron and spin excitations. Ellipsoidal Energy Bands In the absence of a magnetic field the energy and wave function of an electron in an ellipsoidal energy band whose major axis is oriented at an angle to they and z axes (Fig.
2- Wee + 2 Wpoh --2- Weh (85) 46 E. Burstein e( w )1,, is positive and independent of w and of the polarization of the modes. The dispersion relation for w < wee, Wch is given by (86) The frequency of the propagating modes, which are called Alfven waves (2°), varies linearly with the wave vector, and their velocity is independent of their state of polarization. The attenuation of Alfven waves is proportional to (1/wr). Their attenuation increases as w decreases, unlike that of helicon waves, which is independent of w.
An EC summer school by Sellwood, Astrophysical discs.