A deuterium plasma is heated at the second ion cyclotron harmonic,
PHYSICS · Multi-part · Fermi University Physics · Plasma Physics · Waves in plasmas · Kinetic theory, collisions and transport
Plasma Physics, Ch Hot plasmas and free energy: beam instabilities, cyclotron damping and Bernstein waves
Problem
A deuterium plasma is heated at the second ion cyclotron harmonic, ω=2ΩD, where ΩD=eB/mD is the deuteron gyrofrequency.
((a)) Explain, referring to the cold-plasma functions R and L of the Stix dielectric tensor (Chapter 9), why ω=2ΩD is not a resonance of the cold magnetised plasma, and explain, using the Bessel generating function and the helical-orbit derivation of the hot magnetised response, why deuterons can nonetheless absorb power there.
((b)) For the same plasma, ωpD/∣ΩD∣=1.5. An ion Bernstein branch starts, as k⊥rLD→0, with rLD the deuteron thermal Larmor radius, at the ion analogue of the upper hybrid frequency, ωUH,i=(ωpD2+ΩD2)1/2. Evaluate this frequency as a multiple of ∣ΩD∣ and state which two consecutive cyclotron harmonics it lies between.