Old tail lobes effect on the solar-wind – Magnetosphere energy transport for the 27 August 2001 substorm

Abstract The magnetic flux of tail lobes Ψ is divided in two parts of comparable values Ψ 1 and Ψ 02 , with the first that appears during substorm and the second, observed before substorm start. The first was named “new magnetic flux”, the second – “old magnetic flux”. The first, Ψ 1 , is known to play a definitive role in the energy transport from the solar wind into the magnetosphere-ionosphere-atmosphere system, but the role of Ψ 02 in this transport is not well known. From the 27 August 2001 substorm data we study the involvement in the above transport process of the old flux Ψ 02 . This involvement is observed in the polar cap (PC) area, which existed prior to the substorm and is called respectively “the old PC”. In this study, as distinct from earlier works, we use the balance equation of the energy stored in magnetosphere and energy consumed. Activation of the old PC magnetic flux Ψ 02 was found to increase the energy input by ∼85% in the event under consideration.