ISSN:
1089-7666
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The integral equation for the magnetic compressional mode, accounting for geometrical effects along the field line and using the eikonal approximation across the field line, is solved numerically for the eigenvalues and eigenfunctions. These results reproduce the analytic estimates when there is strong drift reversal. The representation of the eigenfunction of the form Bˆ(parallel)=[C(ψ)/B] ×(dP⊥h/dψ) is found to give accurate growth rates over a large range of parameter values. For typical EBT-S [Plasma Phys. 25, 597 (1983)] parameters, instability is predicted for all pressure scale lengths just below those needed for drift reversal, i.e., ||R ∂(Pc) +P⊥h)/2B2 ∂r||〉1 (where P is the article pressure, c and h refer to cold and hot components, B is the midplane magnetic field, and R is the midplane radius of curvature). If larger core densities are present, a wave–particle resonance arises when the particle drifts are not reversed, causing instability up to much larger pressure scale lengths. Stability for all values of the ratio of hot electron density to core density is obtained with ||R ∂Pc/B2 ∂r||〉1+P(parallel)h/P⊥h.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.865914
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