COSPAR 2019

Is any symmetry at the surface of the Sun possible

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Physics, IAS, Mangalayatan University, Aligarh - 202145, Aligarh, Uttar Predesh, India

In 1938, Forbush1 reported 27-day period in cosmic ray intensity, which was explained on the basis of rotation of the Sun. Much later, second sub harmonics of one solar rotation period was observed2, which arises due to active regions present 180o apart and third sub harmonics of one solar rotation period ( 9.0 days) in cosmic-ray intensity is reported to be coupled with the interplanetary parameters3. Recently, one solar rotation period ( 27.0 days) and its second ( 13.5 days), third ( 9.0 days), fourth ( 6.8 days), fifth ( 5.5 days), sixth ( 4.4 days) sub harmonics have been reported during solar minimum4, 5 and during solar polarity reversal periods6 of the solar cycles. In addition to these sub harmonics, signatures of 3.9, 2.8, 2.4 and 1.8 days and 3.8, 3.3, 2.2, 1.8 and 1.7 days periods were also found in solar wind plasma and cosmic rays intensity indicators during solar polarity reversals and minimum periods respectively. These sub harmonics (fourth, fifth and sixth) and other periods did not appear by chance as these periods come out with strong signatures and significant amplitudes during minimum4,5 as well as polarity reversals6. The wavelet study of high resolution data reveals significant variations of 1.7, 2.4, 2.8, 3.3, 3.8 days periods in interplanetary electric field (Ey), south ward component of magnetic field (Bz) and geomagnetic index (AE). The periods 6.8 day, 5.5 day, 4.4 day, 3.9 day, 3.4 day, 3.0 day, 2.8 day, 2.4 day, 2.2 day, 2.0 day, 1.9 day, 1.8 day; and 1.7 day are close to integral multiples (by factors of 1/4, 1/5, 1/6, 1/7, 1/8, 1/9, 1/10, 1/11, 1/12, 1/13, 1/14, 1/15 and 1/16) of one solar rotation period ( 27.0 days), hence could be sub harmonics of fundamental period. These results lead to infer some sort of simultaneous oscillations of active regions having integral multiple frequencies and non-uniform amplitudes occurring on the solar disc.

Yatendra Singh
Yatendra Singh








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