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The Response of the Magnetosphere to Sunspots as Indicated by Geomagnetic Storminess Levels
Author(s) -
Chernosky Edwin J.
Publication year - 1971
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs006i005p00579
Subject(s) - earth's magnetic field , sunspot , magnetosphere , physics , solar flare , atmospheric sciences , geomagnetic storm , solar minimum , astrophysics , solar wind , solar cycle , magnetic field , quantum mechanics
The rather well defined level of geomagnetic activity that occurs with developing sunspots has been examined by using 38 years of daily geomagnetic Ap activity indices and sunspot number Rz. It is found that the Ap values between about 70 and 160 are characteristically associated with sunspots that develop rapidly and reach a peak in number about three days before the occurrence of these levels of Ap . The daily Kp sums from about 45 to 55 were found earlier to be similarly associated with Rz . This relationship predominates at this Ap level during the years in which the average annual Rz is above 50 or more. In quieter solar years some of this range of Ap values tend to be part of a broad recurrence tendency for Rz that peaks about a week before this level of geomagnetic activity is attained; this pattern is a characteristic of a lower level of geomagnetic disturbance. The rapidly developing spots with their high association to solar flares apparently contribute to the magnetospheric energy budget through enhanced electromagnetic radiation. The broad recurrence tendency of lesser disturbance that peaks six to eight days earlier would probably be predominantly due to the Chapman‐Ferraro compression of the magnetosphere by corpuscular emission from the solar ‘ M regions’ of Bartels.