Search Publications
Auroral and sub-auroral phenomena: an electrostatic picture
de Keyser, J.; Echim, M.
Many auroral and sub-auroral phenomena are manifestations of an underlying magnetosphere-ionosphere coupling. In the electrostatic perspective the associated auroral current circuit describes how the generator (often in the magnetosphere) is connected to the load (often in the ionosphere) through field-aligned currents. The present paper examines …
Monopolar and bipolar auroral electric fields and their effects
de Keyser, J.; Maggiolo, R.; Echim, M.
Most of the high-altitude auroral electric fields observed by CLUSTER can be classified into monopolar and bipolar structures. The observations associate monopolar electric fields with polar cap boundary arcs, while bipolar fields tend to be linked to discrete arcs within the auroral oval and to polar cap arcs. The present paper proposes an explan…
Effects of a solar wind dynamic pressure increase in the magnetosphere and in the ionosphere
Milan, S. E.; Kauristie, K.; Amm, O. +4 more
On 17 July 2005, an earthward bound north-south oriented magnetic cloud and its sheath were observed by the ACE, SoHO, and Wind solar wind monitors. A steplike increase of the solar wind dynamic pressure during northward interplanetary magnetic field conditions was related to the leading edge of the sheath. A timing analysis between the three spac…
The Alfvén edge in asymmetric reconnection
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +1 more
We show that in the case of magnetic reconnection where the Alfvén velocity is much higher in the plasma on one side of the current sheet than the other, an Alfvén edge is formed. This edge is located between the electron and ion edges on the high Alfvén velocity side of the current sheet. The Alfvén edge forms because the Alfvén wave generated ne…
Local influence of magnetosheath plasma beta fluctuations on magnetopause reconnection
André, M.; Vaivads, A.; Rème, H. +2 more
We present observations from two subsolar Cluster magnetopause crossings under southward interplanetary magnetic field and strong mirror mode fluctuations in the magnetosheath. In both events the reconnection outflow jets show strong variations on the timescale of one minute. We show that at least some of the recorded variations are truly temporal…
First measurements of electron vorticity in the foreshock and solar wind
Fazakerley, A. N.; Gurgiolo, C.; Goldstein, M. L. +1 more
We describe the methodology used to set up and compute spatial derivatives of the electron moments using data acquired by the Plasma Electron And Current Experiment (PEACE) from the four Cluster spacecraft. The results are used to investigate electron vorticity in the foreshock. We find that much of the measured vorticity, under nominal conditions…
Oxygen ion energization observed at high altitudes
Gunell, H.; Waara, M.; Nilsson, H. +3 more
We present a case study of significant heating (up to 8 keV) perpendicular to the geomagnetic field of outflowing oxygen ions at high altitude (12 RE) above the polar cap. The shape of the distribution functions indicates that most of the heating occurs locally (within 0.2-0.4 RE in altitude). This is a clear example of local…
On the correlation between Broad-Band ELF wave power and ion fluxes in the cusp
Jacobsen, K. S.; Moen, J. I.
We present a study of Broad-Band Extremely Low Frequency (BB-ELF) electric fields in the mid-altitude (4-6 Earth radii) cusp during periods of southward interplanetary magnetic field, using data from the Cluster spacecraft. Magnetospheric boundary layers are identified and classified according to particle precipitation characteristics. We find tha…
On the modeling of planetary plasma environments by a fully kinetic electromagnetic global model HYB-em
Kallio, E.; Pohjola, V.
We have developed a fully kinetic electromagnetic model to study instabilities and waves in planetary plasma environments. In the particle-in-a-cell (PIC) model both ions and electrons are modeled as particles. An important feature of the developed global kinetic model, called HYB-em, compared to other electromagnetic codes is that it is built up …
The influence of Titan on Saturn kilometric radiation
Cecconi, B.; Ye, S. -Y.; Menietti, J. D. +1 more
Previous studies have shown that the occurrence probability of Saturn Kilometric Radiation (SKR) appears to be influenced by the local time of Titan. Using a more extensive set of data than the original study, we confirm the correlation of higher occurrence probability of SKR when Titan is located near local midnight. In addition, the direction fi…