1. Introduction
The solar atmosphere continues to be one of the richest and most dynamic environments studied in modern astrophysics. Spanning many orders of magnitude in density and temperature, while linked to the complex system of magnetic field the sun displays a myriad of interesting phenomenon from sunspots in the photosphere to coronal mass ejections—the most energetic events in the solar system. Like earth, the sun has seasons. More precisely, it has a cycle that lasts about 11 years. The number of sunspots rises and falls and rises again in about 11 years. This is due to the variability of solar magnetic field. The variability of the magnetic field has a strong influence on the dynamics of the outer layer of the sun and is registered by several solar parameters such as the sunspot number, the rate at which flux and coronal mass ejections occur, the flux of solar X-rays and radio waves.
The wealth of solar coronal phenomena called as solar activity should be viewed beyond their individual occurrences [1]. Coronal mass ejections are the most spectacular phenomenon of solar activity. CMEs occur in regions of closed magnetic fields that overlie magnetic inversion lines [2]. A study on CME is an important topic that is related directly to space environment [3]. The sunspot cycle is an important form of solar variability that indicates the extent of closed magnetic field structure on the sun, and hence is important to the study of the origin of coronal mass ejections. Based on the 110 Skylab CMEs, Hildner et al. [4] found the CME rate (R) to be correlated with the sunspot number and obtained the relation R = 0.96 + 0.084 N (based on 7 rotation)
They suggested that this relation is independent of the phase of the solar activity cycle and predicted a rate of 3.2 per day for solar maximum phase.
Webb & Howard [5] studied CMEs from 1973 to 1989 concluding that CME occurrence frequency tends to follow the solar activity cycle in both amplitude and phase. Gopalswamy et al. (2009) [6] have also studied CME occurrence in relation to sunspot number and found that the correlation between them is quite weak during the maximum phase period of solar cycle as compared to that in both ascending as well as descending phase.
Researchers have studied the solar cycle that ended in December 2008 which is known as solar cycle 23. This cycle was longer than normal. The present solar cycle 24 started in December 2008 and is expected to have a shorter time period. In this paper we have studied the relation between various solar features during January 2009 to December 2011 for this cycle.
2. Sources of the Data
Data were obtained from the SOHO-LASCO CME catalogue http://cdaw.nasa.gov/cme_lis/index.html,from the NOAA websites ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/INTERNATIONAL; ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/Flux/penticon_observed,and ftp://ftp.ngdc.noaa.gov/STP/SOLAR_ DATA/Satellite_enviornment/XRay_BGND/GOESBGND.o6 for coronal mass ejection frequency, for sunspot number,for 2800 MHz solar radio emission,and for solar X-ray background, in that order.
3. Data Analysis
Figure 1 shows the variation of different solar parameters during January 2009 to December 2011. The figure shows that the sun is very quiet with less sunspots and solar activity in the beginning of solar cycle 24.