Ground-based Auroral Hiss Recorded at Northern Finland with Reference to Magnetic Substorms

VLF auroral hiss at Kannuslehto (KAN), Finland has been analyzed with a reference to progress of 98 isolated magnetic substorms. During 11 winter months of 2015-2018, 91 of them were accompanied by the auroral hiss during the substorm growth phase. No auroral hiss was recorded during the expansion and recovery phases. We found auroral hiss was observed under rising polar cap PC index showing an increasing input of the solar wind energy into the magnetosphere during the substorm growth phase. We also found that KAN was mapped to the vicinity of enhanced Field Aligned Currents (FACs) during the auroral hiss occurrence. For the first time, it was established that the auroral VLF hiss generation in the equatorial part of the auroral oval (KAN location) is a typical signature of a substorm phase.