Energy input into the upper atmosphere associated with high-speed solar wind streams in 2005

Abstract

A 9 day periodic oscillation in solar wind properties, geomagnetic activity, andupper atmosphere has been reported for the year 2005. To understand the energytransfer processes from the high‐speed solar wind streams into the upper atmosphere, weexamined Joule heating and hemispheric power (HP) from the assimilative mapping ofionospheric electrodynamics (AMIE) outputs for 2005. There are clear 9 day periodvariations in all AMIE outputs, and the 9 day periodic oscillation in the global integratedJoule heating is presented for the first time. The band‐pass filter centered at 9 dayperiod shows that both Joule heating and HP variations are correlated very well to theneutral density variation. It indicates that the energy transfer process into the upperatmosphere associated with high‐speed solar wind streams is a combination of Jouleheating and particle precipitation, while Joule heating plays a dominant role. Thesensitivities of Joule heating and HP to the solar wind speed are close to 0.40 and0.15 GW/(km/s), respectively.