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Unified formulation for inhomogeneity-driven instabilities in the lower-hybrid range
O J G Silveira1, L F Ziebell, R Gaelzer
1Instituto de Física, Universidade Federal do Rio Grande do Sul (UFRGS), Caixa Postal 15051, 91501-970 Porto Alegre, RS, Brazil. omar@if.ufrgs.br
Summary
This study derives an improved dispersion relation for lower-hybrid instabilities, unifying the description of modified two-stream and lower-hybrid drift instabilities in inhomogeneous plasmas.
Area of Science:
- Plasma Physics
- Space Physics
- Astrophysics
Background:
- Inhomogeneous plasmas exhibit complex wave-particle interactions leading to various instabilities.
- Existing formalisms for lower-hybrid range instabilities have inherent ambiguities in describing energy exchange.
Purpose of the Study:
- To derive a corrected local dispersion relation for inhomogeneity-driven instabilities in the lower-hybrid range.
- To provide a unified formulation for instabilities in this frequency range, resolving ambiguities in standard methods.
Main Methods:
- Derivation of a local dispersion relation using a procedure that accurately accounts for wave-particle energy exchange in inhomogeneous media.
- Numerical solutions of the improved dispersion relation to analyze instability characteristics.
Main Results:
- The derived dispersion relation correctly describes energy exchange between waves and particles.
- Numerical solutions confirm a unified formulation for lower-hybrid range instabilities.
- The formulation encompasses the modified two-stream instability (including ion Weibel instability) and the lower-hybrid drift instability.
Conclusions:
- The improved dispersion relation offers a more accurate and unified description of key plasma instabilities.
- This work resolves ambiguities in previous formalisms, enhancing the understanding of plasma behavior in inhomogeneous environments.
- The unified formulation is crucial for studying phenomena driven by cross-field drifts and electron population inhomogeneities.