Measurements of plasma response to driven perturbations in a dipole magnetic field

Measurements of wave–particle interactions are important for the scientific understanding of various plasma phenomena. Laser-induced fluorescence techniques provide non-intrusive, spatially resolved information on the plasma response to electrostatic perturbations. Employing this technique to diagnose plasma fluctuations in dipole magnetic fields can provide insight into wave–particle interactions, mode conversion, and wave reflection and absorption. Externally driven ion acoustic waves are diagnosed as they propagate through the magnetic field gradient in the equatorial region of a permanent magnet. Evidence of reflected waves and strong ion responses is presented for a range of wave frequencies. Results are compared to other observational, simulated, and experimental works.