The newest station in the South African National Antarctic Expedition, the SANAE IV, hostsnumerous research programmes. One is AMIGO which aims to establish the correlationbetween the solar wind and the magnetosphere. A magnetometer, located at a geographicposition of2.83°W, 71.67°S, consisting of two perpendicular coil sensors is installed to detectgeomagnetic field motions, also known as pulsations, in the North-South and East-Westdirections. ([7])The data, treated in this report, cover the years 2003 and 2004 with the exception of the 20first days in January 2003 and another randomly scattered 22 dates during both 2003 and2004 when the data are corrupt or simply just nonexistent.The data consist of detected pulses that are recorded as a voltage, unit m V, which aretransformed into corresponding magnetic flux density amplitudes. The interesting pulsationfrequencies are extracted from the respective powerspectra for certain time intervals. Toconduct this operation a MA TLAB-program that extracts these frequencies is later used toproduce statistics to provide a graspable view of the frequency distribution.The statistics show that the pulsations within the Pc4 range, and specifically the ones close toPc5, are most represented in the data, closely followed by the Pc5 and with a small but yetsignificant representation of frequencies from the Pc3 range. Pc 1 and Pc2 frequencies aredetected sporadically but their existence is negligible at the whole.It is also established that the daytime pulsations are scattered over a wider frequency spectrumthan during evening or morning, with the widest spectrum somewhere around noon ± 2 hours.Some of the results are in acceptable correlation with the theoretical assumptions such aswhere and when the different sources set up the pulsations.

A whistler wave is a Very Low frequency (VLF) trace that obtains its characteristics from dispersive propagation in the magnetosphere. Field-aligned ducts of enhanced plasma density ensure the propagation from one hemisphere to the other. The origin of these signals is lightning strikes that emit radiation which spans the entire spectrum with the bulk being in the VLF band. The VLF portion can travel great distances within the Earth-ionosphere waveguide (EIWG) before penetrating through the ionosphere, and exciting a duct. The relative location, compared to the duct, of those strikes that cause whistlers is unknown. It is of interest to examine where the whistlers that have been observed at Tihany, Hungary, and Dunedin, Nerv Zealand, originate. This is one tool to gain further understanding of the properties, especially the plasma density structure, of the ionosphere and the magnetosphere. Therefore time series with observed whistlers from these stations has been correlated with lightning data obtained from the World Wide Lightning Location Network (WWLLN). The results show that whistlers observed at Tihany mainly originate from lightning in an area surrounding the magnetic conjugate point which is situated in the ocean just off East London, South Africa. This area, called the source region, has a radius slightly less than 1000 km. Whistlers also originate from lightning activity over the rest of Southern Africa and the northern parts of South America. A clear diurnal distinction is seen in that the correlation is maximized when the whistler station and the source region are covered in darkness. This is believed to relate to the diurnal variation of the ionospheric profile, which becomes more transparent to VLF waves at night. A similar diurnal correlation pattern for Dunedin was also obtained. The general correlation results for Dunedin were very sporadic. Whistler statistics for the two stations and lightning statistics for the Tihany's magnetic conjugate point are also presented. It reveals a general diurnal maximum in received whistlers in dark hours for Tihany with absolute maximum at 1 UTC and for Dunedin, the maximum occurs in the afternoon with absolute maximum at 15 UTC. It also reveals a seasonal maximum when the conjugate point is in the summer season. The lightning statistics for Tihany's magnetic conjugate point reveals a diurnal maximurn ranging from the afternoon until a couple of hour after midnight. Something worth noting is the delay between the peaks of lightning activity and whistler registration at Tihany. The lightning activity peaks around 18 UTC. The explanation is once again believed to relate to the behavior of the ionosphere in darkness.

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The mechanism involved in the transfer of energy, momentum and plasma from the solar wind to any planetary magnetosphere is considered one of the more important topics in space plasma physics. With the use of the Mercury spacecraft MESSENGER’s (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) data, it has been possible to study these processes in an environment different, yet similar, to Earth’s. These data have resulted in unprecedented investigations advancing not only the extraterrestrial space plasma research, but also the general space physics field. This work aims to investigate the Kelvin-Helmholtz (KH) instability at Mercury’s magnetopause, which is believed to be one of the main drivers for the transfer of matter and energy into Earth’s magnetosphere, and the low- latitude boundary layer (LLBL) which is in direct connection to the magnetopause. The studies use data from MESSENGER’s magnetometer (MAG) and fast imaging plasma spectrometer (FIPS) instruments during the first three years in orbit. Results show that KH waves are observed almost exclusively on the duskside magnetopause, something that has not been observed at Earth. In contrast, the LLBL shows an opposite asymmetry as it occurs more often on the dawnside. Both the KH instability and the LLBL are observed mainly during northward interplanetary magnetic field. This, together with the distinct opposite asymmetry, suggests that the KH instability and LLBL are somehow connected. Previous theoretical studies, simulations and observations have shown or indicated that the sodium ions have a large impact on the Hermean magnetospheric environment, including the boundary layer where the KH instability arises. One possibility is that the sodium ions also induce the observed dawn-dusk asymmetry in the LLBL. Another explanation could be that the LLBL on its own influences the KH wave occurrence by reducing the KH wave growth rates on the dawnside where most of the LLBLs are observed. Furthermore, observations agree with some formation mechanisms that should give rise to the observed dawn-dusk LLBL asymmetry. The processes responsible for the dawn-dusk occurrence asymmetry in both the KH instability and the LLBL are yet to be confirmed. Future work may also include determination of the contribution of KH waves to the energy and plasma transfer from the solar wind to the Hermean magnetosphere. / <p>QC 20151005</p>

The Cassini mission to Saturn carries a wide variety of instruments to investigate Saturn and its surroundings. Since Cassini is an orbiter, the spatial coverage of this mission far exceeds the few flybys made by earlier spacecraft. We focus on just one of the instruments, and conduct a preliminary analysis of data from five-channel waveform receiver (WFR) which is a part of the Radio and Plasma Wave Science instrument (RPWS). Two electric and three magnetic field components are measured in the 3 Hz to 2.5 kHz band and recorded in the time domain. Interference from other systems of the spacecraft severely complicates interpretation of the electric field spectrum below about 1 kHz. To mitigate this problem we have applied a Blackman-Harris window with a strong sidelobe attenuation, but parts of our analysis is restricted to frequencies above 1 kHz. Various algorithms have been applied to detect and discard erroneous measurements. By analyzing the data we have produced maps of spatial variations in the measured power. The region inside about 9 Saturn radii was found to be particularly active, especially in the electric field measurements. Phenomena that have been seen in the data include dust impacts, electromagnetic whistler-mode hiss and chorus, and electrostatic electron-cyclotron harmonic (ECH) emissions.

In this study density variations in the solar wind are examined based on data from the Cluster Mission. The data are originating from the stream outside the bowshock and thus they are spanning in an interval of three to four months for each mission year up to 2006. As the data are examined, variations above the relative electron density threshold of 1.3 are archived. The variations are analyzed in terms of position, orientation, magnetic field perturbation and scale sizes. The magnetic field perturbations are exhibiting diamagnetic and paramagnetic behavior and a possible link to similar observations inside the magnetosphere is attempted through the impulsive penetration mechanism. The final conclusion of the report is that plasma density enhancements, similar to those identified from previous studies inside the magnetosphere, are also evident in the free solar wind stream close to earth.