Search Publications
Field distributions and shapes of Langmuir wave packets observed by Ulysses in an interplanetary type III burst source region
Nulsen, A. L.; Cairns, Iver H.; Robinson, P. A.
There is no consensus on the mechanisms producing the intense bursty Langmuir wave packets routinely observed in source regions of interplanetary type III radio bursts. Using data from the Ulysses Fast Envelope Sampler (FES) near 4 AU, new analyses of the distributions of wavefields clearly separate the Langmuir waves into "intense localized struc…
Breakdown of the frozen-in condition in the Earth's magnetotail
RèMe, H.; Owen, C. J.; Dunlop, M. W. +3 more
We investigate in detail the breakdown of the frozen-in condition detected by Cluster at the downstream distance of ∼19 RE in the midnight sector of the magnetotail during a substorm expansion on 22 August 2001. It is found that the breakdown occurred (1) in a low-density environment with moderate to large proton plasma flow and signifi…
Cluster observations of an auroral potential and associated field-aligned current reconfiguration during thinning of the plasma sheet boundary layer
Karlsson, T.; Marklund, G.; Johansson, T. +1 more
Cluster observations are used to illustrate the reconfiguration of an auroral potential structure encountered at the poleward boundary of the central plasma sheet within the Southern Hemisphere premidnight auroral oval. The reconfiguration from a symmetric U shape to an asymmetric S shape takes place between two consecutive crossings by Cluster sp…
Evolution of ring current and radiation belt particles under the influence of storm-time electric fields
Nishimura, Y.; Shinbori, A.; Ono, T. +2 more
Electric field and potential distributions in the inner magnetosphere during geomagnetic storms have been investigated using the Akebono/EFD data. Using this electric field, we study injection of ring current particles and acceleration of radiation belt electrons by single-particle calculations. During the main phase, the dawn-dusk electric field …
Large-scale structure of the fast solar wind
Breen, A. R.; Bisi, M. M.; Fallows, R. A. +2 more
We present the results of a comprehensive study of the fast solar wind near solar minimum conditions using interplanetary scintillation (IPS) data taken with the EISCAT system in northern Scandinavia, and a recent extremely long baseline observation using both EISCAT and MERLIN systems. The results from IPS observations suggest that the fast wind …
Geometry of the high-latitude magnetopause as observed by Cluster
Balogh, A.; Zhang, H.; Zong, Q. -G. +3 more
This investigation reveals the geometrical properties of the high-latitude boundaries surrounding the high-altitude cusp. These have been shown by recent studies to include the outer boundary between the magnetosheath and the cusp; the outer boundary between the magnetosheath and the high-latitude, closed field-line region of the dayside magnetosp…
Multispacecraft observations of chorus dispersion and source location
Kletzing, Craig A.; Pickett, Jolene; Chum, Jaroslav +3 more
We report Cluster Wideband Data (WBD) receiver observations of correlated chorus elements with different frequency/time characteristics as seen on multiple spatially separated Cluster spacecraft. Because chorus packets disperse as they propagate, careful comparison of the signals from multiple spacecraft can provide new information about the origi…
Energetic particle observations by Ulysses during the declining phase of solar cycle 23
Forsyth, R. J.; Lanzerotti, L. J.; Marsden, R. G. +4 more
We present recent energetic particle measurements from 1-20 MeV/n recorded by the Ulysses/COSPIN/LET instrument from mid-October to the end of November 2003 and from May 2004 to the end of February 2005. Long-lasting periods with enhanced solar activity occurred during the declining phase of the current solar cycle contributing to the high-intensi…
Evidence for a high-energy tail associated with foreshock field-aligned beams
RèMe, H.; Lucek, E. A.; Parks, G. K. +4 more
The reduced particle distributions of field-aligned beams observed upstream of the bow shock are examined in detail using Cluster spacecraft. We find that the reduced parallel and perpendicular distribution forms can be strongly geometry-dependent. Above a certain critical value of the angle between the local shock normal and the direction of the …
New approach for determining the normal of the bow shock based on Cluster four-point magnetic field measurements
Balogh, A.; Zhang, T. L.; Dunlop, M. +6 more
We introduce a new approach to determine the normal of Earth's bow shock, based on four-point magnetic field measurements. The method obtains the local bow shock normal, based on the assumption that the normal is in the opposite direction to the gradient of the magnetic pressure or magnetic strength (within the shock front). This gradient can be d…