Upper & Lower Hybrid Resonances
Characteristic wave resonance frequencies in magnetized plasmas where wave group velocity vanishes and electromagnetic energy couples efficiently into plasma heating.
Governing formula
Upper: ω_UH = √(ω_pe² + ω_ce²); Lower: 1 / ω_LH² = 1 / (ω_ci² + ω_pi²) + 1 / (ω_ce ω_ci)
SI unit
rad/s (Resonance Frequencies)
In depth
Upper Hybrid Resonance (UHR) involves perpendicular electron oscillations combining plasma frequency and electron cyclotron frequency. Lower Hybrid Resonance (LHR) involves coupled ion-electron motion, widely used for lower hybrid current drive (LHCD) in fusion.
Examples in the real world
Lower Hybrid Current Drive (LHCD) driving non-inductive toroidal plasma currents in tokamaks.