Search Publications
Formation of multiple energy dispersion of H+, He+, and O+ ions in the inner magnetosphere in response to interplanetary shock
Tanaka, T.; Ebihara, Y.; Tsuji, H.
An interplanetary (IP) shock has a large impact on magnetospheric ions. Satellite observations have shown that soon after arrival of the IP shock, overall intensity of the ions rapidly increases and multiple energy dispersion appears in an energy-time spectrogram of the ions. In order to understand the response of the magnetospheric ions to IP sho…
Distribution of Field-Aligned Electron Events in the High-Altitude Polar Region: Cluster Observations
Dunlop, Malcolm; Carr, Chris; Torkar, Klaus +4 more
Field-aligned electrons (FAEs) are important for the energy transport in the solar wind-magnetosphere-ionosphere coupling. However, the distribution of FAEs and the concerning physical mechanism in different altitudes of the polar region are still unclear. In this paper, data from the Cluster spacecraft were used to study the characteristics of FA…
Validation of single spacecraft methods for collisionless shock velocity estimation
Pope, Simon A.; Walker, Simon N.; Collinson, Glyn +1 more
The velocity of a collisionless shock (CS) is an important parameter in the determination of the spatial scales of the shock. The spatial scales of the shock determine the processes that guide the energy dissipation, which is related to the nature of the shock. During the pre-ISEE era, estimations of relative shock-spacecraft velocity (VSh
Quasiperiodic field-aligned current dynamics associated with auroral undulations during a substorm recovery
Marghitu, O.; Vogt, J.; Bunescu, C. +2 more
A substorm recovery event in the early morning sector is explored by means of ground and spacecraft data. The ground data are provided by stations of the MIRACLE network, in northern Scandinavia and Svalbard, while spacecraft data are observed by the Cluster satellites, toward the end of the recovery phase. Additional information is provided by th…
Swept Forward Magnetic Field Variability in High-Latitude Regions of Saturn's Magnetosphere
Coates, A. J.; Dougherty, M. K.; Masters, A. +3 more
Swept forward field is the term given to configurations of magnetic field wherein the field lines deviate from the meridional planes of a planet in the direction of its rotation. Evidence is presented for swept-forward field configurations on Cassini orbits around Saturn from the first half of 2008. These orbits were selected on the basis of high …
Concerning the helium-to-hydrogen number density ratio in very slow ejecta and winds near solar minimum
Farrugia, C. J.; Galvin, A. B.; Vasquez, Bernard J. +2 more
Near the solar minimum the average value of the helium-to-proton number density ratio is a strong function of speed. The average ratios for both solar ejecta and ambient winds obey approximately the same relation with speed. At the lowest speeds, the ratio takes on small values near and below 0.01. Here winds and ejecta with very slow speeds (≲310…
An analysis of magnetic reconnection events and their associated auroral enhancements
Reistad, J. P.; Milan, S. E.; Case, N. A. +2 more
An analysis of simultaneous reconnection events in the near-Earth magnetotail and enhancements in the aurora is undertaken. Exploiting magnetospheric data from the Geotail, Cluster, and Double Star missions, along with auroral images from the IMAGE and Polar missions, the relationship between a reconnection signature and its auroral counterpart is…
Electron scattering by magnetosonic waves in the inner magnetosphere
Hospodarsky, G. B.; Kurth, W. S.; Ma, Qianli +4 more
We investigate the importance of electron scattering by magnetosonic waves in the Earth's inner magnetosphere. A statistical survey of the magnetosonic wave amplitude and wave frequency spectrum, as a function of geomagnetic activity, is performed using the Van Allen Probes wave measurements and is found to be generally consistent with the wave di…
Highly relativistic radiation belt electron acceleration, transport, and loss: Large solar storm events of March and June 2015
Baker, D. N.; Kanekal, S. G.; Zhao, H. +12 more
Two of the largest geomagnetic storms of the last decade were witnessed in 2015. On 17 March 2015, a coronal mass ejection-driven event occurred with a Dst (storm time ring current index) value reaching -223 nT. On 22 June 2015 another strong storm (Dst reaching -204 nT) was recorded. These two storms each produced almost total loss of radiation b…
Electrostatic solitary waves and electrostatic waves at the magnetopause
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +1 more
Electrostatic solitary waves (ESWs) are characterized by localized bipolar electric fields parallel to the magnetic field and are frequently observed in space plasmas. In this paper a study of ESWs and field-aligned electrostatic waves, which do not exhibit localized bipolar fields, near the magnetopause is presented using the Cluster spacecraft. …