Morphological study of active region causing coronal mass ejection related geomagnetic storm and its effects to geomagnetic induced current (GIC) / Nurain Mohamad Ansor

Geomagnetic storm has been one of greatest events in space weather studies. Apart from
the formation of aurora, geomagnetic induced current (GIC) is also induced during the
storm when the storm intensity gets severe. The most common source that triggers this
phenomenon is coronal mass ejection (CME) and it has been widely proven in past
studies. CME is a massive eruption created by the Sun and occurs at active regions (AR)
where intense magnetic field is built up. This region is called as AR due to solar
activities (flares and CME) taking place at this area. Comprehensive studies on the
structure and properties of AR are needed and very important in understanding the
formation of CME variation in terms of their speed, angular width and the effects on
storms that are triggered afterwards. Thus, this research is aimed to analyze the
morphology of AR that initiate geomagnetic storm which include AR parameters
(magnetic classification, McIntosh classification of sunspot groups and size of sunspot)
and geomagnetic storm properties (Kp- index and CME speed) and to study the
relationship between the intensity of geomagnetic storm and geomagnetic induced
current (GIC). It focuses on 37 geomagnetic storm events that occurred in 2017. The
raw data of AR and geomagnetic storm parameters were obtained from verified
databases – Space Weather Live, National Aeronautics and Space Agency (NASA) and
National Oceanic and Atmospheric Administration (NOAA). The data was then
analyzed by using Principal Component Analysis (PCA) method in studying the
morphology of AR, while study on the relationship between storm intensity and GIC
was conducted qualitatively by using descriptive approach. The research found that size
of sunspot is the most potential AR parameter that determines the formation of fast-
moving CME that has caused multiple geomagnetic storms in 2017. Another result from
this research deduced that GIC activity is directly proportional to storm intensity,
whereby, GIC became more fluctuating as storm was getting more intense. This is
believed due to the ionospheric disturbances that modified the magnitudes of magnetic
field and thus, electric field was induced on the ground and underneath of it.