Investigations Of Variability In Space Weather Conditions Using Advanced Wavelet Analysis Techniques

Abstract

Space weather means changes in the near-Earth space environment. It is caused by varying conditions within the Sun's atmosphere. The Sun emits a continuous stream of highly energetic particles and radiation of varying intensity. The surface of the Sun covers the large scale strong magnetic field as sunspots. After the discovery of the telescope around 1610, the systematic observation of sunspots started. It was found that the number of sunspots on the surface of the Sun varies cyclically with time, going through repeated descending and ascending phase of a cycle. This cyclic variation of the sunspot number has an average period of about 11 years and is known as the solar cycle or the sunspot cycle or the solar activity cycle. Sunspots are the main sources of several events like solar flares, eruptions, and coronal mass ejections. These events have serious and sometimes hazardous effects on space weather, satellites, air traffic on polar routes and modern-day technologies (telecommunication and electric power grids at high latitudes). Sunspot cycle has an important effect on the space environment and the Earth climate system. In the pre-industrial era, the Sun was the main driver for the earth's global temperature. Therefore, understanding the solar cycle is not only important to the solar and the stellar physics communities, but also to the space weather and the Earth climate communities. Solar activities are related to the magnetic fields of Sun. The strength of the magnetic field at a typical point on the solar surface is a few gausses. However, it can be much higher in sunspots. Sometimes the value of the magnetic field is strong due to which Solar flares occur. Solar flares cause geomagnetic storms, which affect the earth in numerous significant ways. The origin of the Solar wind is complex and the region of Solar wind acceleration has not been probed properly. Several publications discuss the variation in Solar wind parameters which have durations of hours and boundary widths of tens of minutes. These variations in the solar wind parameter can also lead to a better understanding of the nature and properties of the solar wind plasma, the stability (or lack thereof) of these structures, and the character of plasma instabilities.