Nighttime Pc3 pulsations: MM100 and MAGDAS observations

Abstract

In this paper, we present a statistical and case analysis of nighttime Pc3 pulsations observed from middle to equatorial latitudes during the year 2003. We found two groups of nighttime Pc3 pulsations. Pc3s of the first group are in fact the nightside counterpart of morning Pc3 pulsations with large azimuthal scales slowly attenuating toward midnight. Such night signatures of morning Pc3 waves are observed during the periods of fast solar wind (V > 500 km/s). The second type is the locally generated night Pc3 pulsations. They can be observed under moderate solar wind velocities. Maximal occurrence rates and amplitudes for these pulsations are recorded at middle geomagnetic latitudes near the local magnetic midnight. Probably, they are associated with auroral activations or local non-substorm bursty processes.

Preliminary Pc3-pulsations analysis at conjugate stations using continuous wavelet transform

“…This work uses data of the period between 01:00 UT and 04:00 UT on 25th UT October 2016 which corresponds to a geomagnetically disturbed period (Kp = 3). Previous studies have shown that most cases of Pc3 occur in the range of 1 < Kp < 3.5 (Jacob 1970, Yagova et al, 2017. Fortunately, the period of the storm was close to the September equinox, which ensures equally illumination by the Sun on both Earth's hemispheres.…”

“…Pc3 pulsations happen mainly due to the transmission into the magnetosphere of interplanetary upstream waves (Greenstadt et al, 1980;Ndiitwani & Sutcliffe 2009) generated through ioncyclotron instability by protons reflected off the bow shock along the interplanetary magnetic field (IMF) lines (Francia et al, 2009). Some earlier studies have reported that Kelvin-Helmholtz instability (KHI) at the flanks of the magnetopause was often considered as a possible mechanism of Pc3 pulsations (Yagova et al, 2017). On the other hand, the wave structure may be affected by cavity modes (Menk et al, 2000).…”

A technique for detection of ULF Pc3 waves and their statistical analysis

“…Automatic selection of Pc3 events has been made with an algorithm based on the analysis of PSD, calculated with Blackmann-Tukey technique [Kay, 1988], in a running window with duration 12.8 min with 3-min time step. This method was applied earlier for automatic selection of Pc2-3 pulsations recorded in space [Yagova et al, 2015] and on the ground .…”

“…Upon this propagation, a part of a fast magnetosonic mode energy is resonantly converted into Alfven field line oscillations in the inner magnetosphere [Yumoto, 1988]. Therefore, spectra of ground signals are formed as a combination of the upstream wave spectra and the magnetospheric resonant response [Vellante et al, 1995]. The resonant conversion is most clearly revealed in component, and much weaker in component [Pilipenko et al, 1999].…”

Magnetic Data Acquisition System (MAGDAS) Malaysia: Installation and Performance Analysis of Local Data Logger with Kyushu University Data Logger at USM Transkrian, Pulau Pinang

“…The speed of the solar wind can be divided into two types which are low-speed and high-speed. For low-speed solar winds move less than 400km s -1 and for high-speed solar, wind moves at 400 to 800 km s -1 [1], [2], [16]. Usually, high-latitude region magnetic field activity varies effectively with the high-speed solar wind streams.…”