dorsal/arxiv
View SchemaNegative-energy perturbations in cylindrical equilibria with a radial electric field
| Authors | G. N. Throumoulopoulos, D. Pfirsch |
|---|---|
| Categories | |
| ArXiv ID | physics/9709007 |
| URL | https://arxiv.org/abs/physics/9709007 |
| DOI | 10.1103/PhysRevE.56.5979 |
Abstract
The impact of an equilibrium radial electric field $E $ on negative-energy perturbations (NEPs) (which are potentially dangerous because they can lead to either linear or nonlinear explosive instabilities) in cylindrical equilibria of magnetically confined plasmas is investigated within the framework of Maxwell-drift kinetic theory. It turns out that for wave vectors with a non-vanishing component parallel to the magnetic field the conditions for the existence of NEPs in equilibria with E=0 [G. N. Throumoulopoulos and D. Pfirsch, Phys. Rev. E 53, 2767 (1996)] remain valid, while the condition for the existence of perpendicular NEPs, which are found to be the most important perturbations, is modified. For $|e_i\phi|\approx T_i$ ($\phi$ is the electrostatic potential) and $T_i/T_e > \beta_c\approx P/(B^2/8\pi)$ ($P$ is the total plasma pressure), a case which is of operational interest in magnetic confinement systems, the existence of perpendicular NEPs depends on $e_\nu E$, where $e_\nu$ is the charge of the particle species $\nu$. In this case the electric field can reduce the NEPs activity in the edge region of tokamaklike and stellaratorlike equilibria with identical parabolic pressure profiles, the reduction of electron NEPs being more pronounced than that of ion NEPs.
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"abstract": "The impact of an equilibrium radial electric field $E $ on negative-energy\nperturbations (NEPs) (which are potentially dangerous because they can lead to\neither linear or nonlinear explosive instabilities) in cylindrical equilibria\nof magnetically confined plasmas is investigated within the framework of\nMaxwell-drift kinetic theory. It turns out that for wave vectors with a\nnon-vanishing component parallel to the magnetic field the conditions for the\nexistence of NEPs in equilibria with E=0 [G. N. Throumoulopoulos and D.\nPfirsch, Phys. Rev. E 53, 2767 (1996)] remain valid, while the condition for\nthe existence of perpendicular NEPs, which are found to be the most important\nperturbations, is modified. For $|e_i\\phi|\\approx T_i$ ($\\phi$ is the\nelectrostatic potential) and $T_i/T_e \u003e \\beta_c\\approx P/(B^2/8\\pi)$ ($P$ is\nthe total plasma pressure), a case which is of operational interest in magnetic\nconfinement systems, the existence of perpendicular NEPs depends on $e_\\nu E$,\nwhere $e_\\nu$ is the charge of the particle species $\\nu$. In this case the\nelectric field can reduce the NEPs activity in the edge region of tokamaklike\nand stellaratorlike equilibria with identical parabolic pressure profiles, the\nreduction of electron NEPs being more pronounced than that of ion NEPs.",
"arxiv_id": "physics/9709007",
"authors": [
"G. N. Throumoulopoulos",
"D. Pfirsch"
],
"categories": [
"physics.plasm-ph"
],
"doi": "10.1103/PhysRevE.56.5979",
"title": "Negative-energy perturbations in cylindrical equilibria with a radial electric field",
"url": "https://arxiv.org/abs/physics/9709007"
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