TY JOUR TI ULF wave power index for space weather and geophysical applications: A review KW ULF waves KW space weather KW substorms KW magnetic storms KW earthquake precursors KW geomagnetically induced currents KW discrete mathematical analysis JO Russian Journal of Earth Sciences AU , .. AU , .. AU , .. AU , .. PY 2017 IS 17 PB Геофизический центр Российской Академии Наук