Energy deposition of a Pc5 ULF wave in the polar ionosphere measured by EISCAT

Ultra low frequency (ULF) waves can contribute significantly to energy and momentum transfer between the Solar Wind – magnetosphere – ionosphere system, however, the energy deposition by ULF waves is often not taken into account in the global energy budget. A case study of spatial and temporal energy deposition of a Pc5 (2 – 7 mHz) ULF wave during non-sunlit conditions is presented. Datasets from the EISCAT Tromsø VHF radar, magnetometers and DMSP satellites were utilized to estimate the wave characteristics and the height-dependent energy deposition rates. The equipartition of energy into the ionosphere through thermal, ion frictional and/or Joule heating are discussed. The goal of this study is to quantify how much energy is deposited by ULF waves in otherwise quiet conditions.