Gnevyshev peaks in solar radio emissions at different frequencies

R P Kane

doi:10.5194/angeo-27-1469-2009

Abstract

Abstract. Sunspots have a major 11-year cycle, but the years near the sunspot maximum show two or more peaks called GP (Gnevyshev Peaks). In this communication, it was examined whether these peaks in sunspots are reflected in other parameters such as Lyman-α (the chromospheric emission 121.6 nm), radio emissions 242–15 400 MHz emanating from altitude levels 2000–12 000 km, the low latitude (+45° to −45°) solar open magnetic flux and the coronal green line emission (Fe XIV, 530.3 nm). In the different solar cycles 20–23, the similarity extended at least upto the level of 609 MHz, but in cycle 22, the highest level was of 242 MHz. The extension to the higher level in cycle 22 does not seem to be related to the cycle strength Rz(max), or to the cycle length.

Highlights

Two or more peaks can be identified during the sunspot maximum years
In recent publications (Kane, 2006, 2007, 2008a, b, c), it was pointed out that these GPs have a solar latitude dependence, with peaks shifting with time from higher to lower latitudes as in the Maunder butterfly diagram, and the peaks in sunspots are similar to those in other electromagnetic ra
But as a further precaution, we deleted daily val- plots are for radio emissions 15 400, 8800, 4995, 2695 (2800 ues deviating by more than 30% from the monthly mean. as superposed crosses), 1415, 609, 410 and

Summary

Introduction

Two or more peaks can be identified during the sunspot maximum years This splitting of activity was identified for the first time in the green corona line intensity data by Gnevyshev (1967, 1977) and later for several solar and interplanetary phenomena (details in the review by Storini et al, 2003). These will be termed as GPs (Gnevyshev Peaks). Data are available for other solar radio emissions at several other frequencis Temperature (K) (abscissa, bottom) and plasma density P (abscissa, top; note the reversed scale for P , increasing from right to the left))

Characteristics of solar atmosphere

Findings

Conclusions and discussions