Identification of Fractal Properties in Geomagnetic Data of Southeast Asian Region during Various Solar Activity Levels

Abstract

The fractal properties of geomagnetic northward component data (H-component) in the equatorial region during various phases of solar activity over Southeast Asia were investigated and then quantified using the parameter of the Hurst exponent (H). This study began with the identification of existence of spectral peaks and scaling properties in international quiet day H-component data which were measured during three levels of solar activity: low, intermediate, and high. Then, various cases of quiet and disturbed days during different solar activity levels were analyzed using the method that performed the best in the preceding part. In all the years analyzed, multifractal scaling and spectral peaks exist, signifying that the data have fractal properties and that there are external factors driving the fluctuations of geomagnetic activity other than solar activity. The analysis of various cases of quiet and disturbed days generally showed that quiet days had anti-persistence tendencies (H < 0.5) while disturbed days had persistence tendencies (H > 0.5)—generally a higher level of Hurst exponent compared to quiet days. As for long-term quiet day H-component data, it had a Hurst exponent value that was near H ≃ 0.50, while the long-term disturbed day H-component data showed higher values than that of the quiet day.

On the Relationship between the Fractal Dimension of Geomagnetic Variations at Altay and the Space Weather Characteristics

“…In general, this result coincided with the results of the papers mentioned in the introduction. It should be noted that, in our calculations, a statistically reliable relationship of HFD with the space weather characteristics was revealed for all components of the geomagnetic field (H, D, Z), while in previous studies [6][7][8][9], a significant decrease in HFD with geomagnetic disturbances was noted only for the horizontal component.…”

“…The relationship between the fractal dimension of geomagnetic variations and magnetic storms has been studied by many researchers [4][5][6][7][8][9][10]. Moreover, the fractal dimension of fluctuations in geomagnetic indices, such as AE [11], Sym-H [12],and Dst [13], which are the result of the processing of measurements at several magnetic observatories, were studied.…”

“…Moreover, the fractal dimension of fluctuations in geomagnetic indices, such as AE [11], Sym-H [12],and Dst [13], which are the result of the processing of measurements at several magnetic observatories, were studied. The majority of studies noted the effect of reducing the fractal dimension of geomagnetic variations or fluctuations in geomagnetic indices during geomagnetic disturbances at high [11] and low latitudes [5,7]. Wanliss and co-authors [8] showed that the fractal dimension of geomagnetical variation increased with geomagnetical latitude.…”

The Variation of Counter-Electrojet Current at the Southeast Asian Sector during Different Solar Activity Levels

“…EEJ current exists within ±3 • dip equator in the E region of the ionosphere and forms a narrow band-like current with an eastward direction at the equator. EEJ current can be monitored through the daytime variation of ground equipment's horizontal geomagnetic field component (H-component) [1,2]. Occasionally, the H-component is temporarily depressed below the night-time level as the current flow reverses to the west.…”

Editorial to the Special Issue “Space Weather”

“…The paper of [23] presents the fractal properties of geomagnetic data in the equatorial region of Southeast Asia during low, intermediate and high phases of solar activity using the Hurst exponent (H) as the parameter. In particular, they utilized the geomagnetic northward component data (H-component) obtained from two magnetometer stations of Langkawi, Malaysia (LKW) and Davao, Philippines (DAV).…”