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The PC Index Variations During 23/24 Solar Cycles: Relation to Solar Wind Parameters and Magnetospheric Disturbances
Author(s) -
Troshichev O. A.,
Dolgacheva S. A.,
Stepanov N. A.,
Sormakov D. A.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028491
Subject(s) - solar wind , magnetosphere , physics , interplanetary magnetic field , coronal mass ejection , earth's magnetic field , atmospheric sciences , solar maximum , space weather , dynamic pressure , environmental science , meteorology , magnetic field , mechanics , quantum mechanics
The polar cap magnetic activity PC index is regarded as indicator of the solar wind energy that enters into the magnetosphere during the solar wind‐magnetosphere coupling (Resolutions of XXII IAGA Assembly, 2013). This study presents the results of statistical analysis of relationships between the yearly values of PC index and such indicators as the magnetic activity indices ( AE and Dst ), the solar wind parameters (velocity Vsw , density Nsw , dynamic pressure Pdy n, vertical interplanetary magnetic field (IMF) component Bz , total IMF field |B| , electric field E KL ), and the solar activity parameters (sunspot number, coronal mass ejections, stream interaction regions) in course of 23–24 solar cycles. It is shown that the yearly values of the quiet daily curve magnitude (which serves as a level of reference in estimation of the PC index value) changed during 1998–2019 in remarkable agreement with variation of the Solar UV irradiation (150–200 nm) absorbed in the Earth's ionosphere. The yearly values of PC index perfectly correlate with the yearly values of Vsw and |B| and their product electric field E KL , as well as with the yearly values of AE and Dst indices testifying that PC index serves as the ground‐based indicator of the solar wind energy input into the magnetosphere. The yearly values of E KL , PC , AE , Dst correlate with the total IMF field |B| much better that with the IMF Bz component, testifying that efficiency of the solar wind impact on the magnetosphere is defined by the total IMF value, in contrast with Dungey's concept of reconnection.