Periodicities in the X-Ray Emission From the Solar Corona

Abstract

We have studied the time series of full disk integrated soft and hard X-ray emission from the solar corona during 2004 January to 2008 December, covering the entire descending phase of solar cycle 23 from a global point of view. We employ the daily X-ray index derived from 1 s cadence X-ray observations from the Si and CZT detectors of the "Solar X-ray Spectrometer" mission in seven different energy bands ranging between 6 and 56 keV. X-ray data in the energy bands 6-7, 7-10, 10-20, and 4-25 keV from the Si detector are considered, while 10-20, 20-30, and 30-56 keV high energy observations are taken from the CZT detector. The daily time series is subjected to power spectrum analysis after appropriate correction for noise. The Lomb-Scargle periodogram technique has shown prominent periods of ∼13.5 days, ∼27 days, and a near-Rieger period of ∼181 days and ∼1.24 yr in all energy bands. In addition to this, other periods like ∼31, ∼48, ∼57, ∼76, ∼96, ∼130, ∼227, and ∼303 days are also detected in different energy bands. We discuss our results in light of previous observations and existing numerical models.

Short-term periodicities in interplanetary, geomagnetic and solar phenomena during solar cycle 24

“…For typical solar parameters, Lou's theoretical model results to periodicities which are very close to the observed ones (Chowdhury et al 2013b and references there in).…”

“…These periods were also detected in the north-south asymmetry data of sunspot area during end of 2010 to middle of 2012 (Chowdhury et al 2013a) and also in the power spectra of soft and hard X-ray emission from the so- (Chowdhury et al 2013a(Chowdhury et al , 2013b.…”

“…Recently, Rieger-type periodicity in the range of 156 +19 −9 days in the occurrence rate of solar coronal type III radio bursts was detected during the time interval from 2000 June 22 to 2003 December 31 (Lobzin et al 2012) and ∼ 181 day period in the fluctuation of coronal X-ray emission during descending phase of cycle 23 (Chowdhury et al 2013b). During solar cycle 23, a number of researchers have reported the existence of Rieger and Rieger type periods in different data sets like sunspot number and area (Chowdhury et al 2009;Chowdhury and Dwivedi 2011;Singh and Badruddin 2014), photospheric magnetic flux (Ballester et al 2004;Knaack et al 2005); occurrence rate of CMEs (Lara et al 2008;Lou et al 2003); IMF and energetic particle events (Richardson and Cane 2005).…”

“…For all these data sets, we have computed the Lomb-Scargle (L-S) periodogram (Lomb 1976;Scargle 1982;Horne and Baliunas 1986;Bai 2003;Chowdhury et al 2013aChowdhury et al , 2013b, by calculating the Scargle normalized periodogram P N (ω). This is an important algorithm for time series analysis of unevenly sampled data and quite robust at finding and testing the significance of weak periodic signals through false alarm probability (FAP), a simple estimate of the significance of the height of a peak in the power spectrum can be derived.…”

Midterm periods of solar filaments

“…So we compare the midterm periods of coronal green line index and F 10.7 cm from Kane's work [ Kane , ] and the FSFNs in the present work from cycles 18 to 21 and show in Table . We find that the solar corona layer activities also have the midterm periodicity [ Chowdhury and Dwivedi , ; Chowdhury et al , ]. It is well noted that the one ∼1 year (about 11–13 months) period frequently occurs in each cycle of FSFNs and coronal green line index, also often occurs in each cycle of LSFNs and sunspot numbers in Table .…”