Cyclotron absorption and emission in mode conversion layers—a new paradigm

Abstract

When the analysis of absorption with mode conversion effects included began to mature in recent years, the study of the corresponding effects on emission began and has led to some surprising results. The classical expressions for cyclotron or synchrotron emission from a harmonic resonance were originally derived from models that did not include mode conversion or its attendant reflection, and classical expressions for the optical depth and opacity were obtained. When mode conversion was included, the principal surprise was that the transmission coefficient, which was understood as being due to absorption, is totally independent of absorption and due exclusively to tunneling. The other surprise from the mode conversion analysis is that the observed emission arises from two distinct sources, one direct and one from an indirect Bernstein wave source which is partially converted in the cyclotron layer to outgoing electromagnetic waves, with the net result that mode conversion cancels out for the electron case, but not for ions. The only corrections to electron cyclotron emission are then due to reflection effects, and these have been shown to be small for many laboratory plasmas, leading to the validation of the classical formula for these cases, but via an entirely new paradigm in its interpretation. This review includes a summary of the absorption process for both electron and ion cyclotron harmonics, and reviews carefully the emission physics, including both potential error estimates and a discussion of the emission source distribution in space.

A closed high-frequency Vlasov–Maxwell simulation model in toroidal geometry

“…Now, a closed Vlasov-Maxwell system is constructed using the weight evolution equations, including equations (1) and 3for full-f simulation or (16) and (17) for perturbative δf simulation, together with the gyrokinetic Poisson's equation (9) and Ampère's law (10).…”

“…Radio frequency (RF) waves have been proven to be an effective approach to plasma heating [1] and current drive [2] in magnetic confinement fusion plasmas, and are essential for the startup of a fusion reactor and its steady state operation thereafter. RF wave launching is also important to improve confinement, and to maintain H-mode runs of Tokamaks.…”

Energy Balance of Controlled Thermonuclear Fusion

“…Nevertheless, in order to convert the cyclotron or synchrotron radiation into the kinetic energy of electrons, a very diverse proposal for the re-absorption has been forwarded [3,4]. The magnetic fusion rests solely upon this proposal [5,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. It applies erroneously the black body radiation and the related Kirchhoff's law to calculate the re-absorption coefficient of the cyclotron or synchrotron radiation by the free-spiraling electrons of the plasma.…”

“…The significance of energy loss by radiation from a thermonuclear plasma was recognized already at the early stage of fusion research [1][2][3][4][5]. However, although the basic physical processes that lead to emission, absorption and scattering of radiation or photon by bound and free electrons are all known, recognized and well established [6][7][8][9][10][11][12][13][14][15][16][17], regarding the radiation losses, there persists a discrepancy between basic physics [6][7][8][9][10][11][12][13][14][15][16][17] and its application to a fully ionized thermonuclear plasma [3][4][5][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Whereas the basic processes conclusivel...…”

Normal modes and resonant confinement of charged particles in oscillating electric and magnetic fields

“…This problem finds applications in many areas of physics and technology. These include the development of cyclotron accelerators [1], free electron lasers [2], plasma physics [3] and the description of some atmospheric phenomena [4,5]. In a review on the motion of charges in condensed matter, Pan [6] states that there are over 500 galvanometric effects in solids.…”