Fig. 2: The auroral images and the corresponding magnetosphere measurements.
From: Evidence for Alfvén waves powering auroral arc via a static electric potential drop
a The auroral image taken by THEMIS ASI (white light, raw count) in the northern hemisphere. The image is presented in the plane of magnetic latitude (MLat) in degree (\(\circ\)) and magnetic local time (MLT) in hour (h). b The auroral image taken by DMSP F19 SSUSI (UV emission, calibrated to energy flux) in the southern hemisphere. The footprints of RBSP-A and B are mapped using the T04 storm-time magnetic model77. c The magnetic field lines connecting the magnetosphere and ionosphere. The locations of RBSP-A and -B and DMSP F19 are marked along the highlighted magnetic field line. d The elevation angle (\(\theta={\sin }^{-1}{B}_{z}/{|B|}\)) of the magnetic field measured by the two RBSP satellites, showing strong perturbations when crossing the magnetic field lines threading the auroral arc.
