Search Publications
Determination of the solar wind slowdown near solar maximum
Wang, C.; Richardson, J. D.
The magnitude of the solar wind speed decrease from the inner to the outer heliosphere provides important information about the interaction of the heliosphere with the local interstellar medium (LISM), leading to better estimates of the size and shape of the heliosphere and of the LISM density. In this study we combine observations from multiple s…
A parametric study of the influence of ion and electron properties on the excitation of electromagnetic ion cyclotron waves in coronal mass ejections
Farrugia, Charles J.; Dasso, Sergio; Gratton, Fausto T.
Interplanetary coronal mass ejections (ICMEs) often possess a negative proton thermal anisotropy, Ap = T⟂,p/T∥,p - 1 < 0 (T∥, T⟂: parallel and perpendicular temperatures, respectively) so that right-hand polarized electromagnetic ion cyclotron waves (EICWs) may be amplified by a kinetic ins…
Modeling the propagation of solar energetic particles in corotating compression regions of solar wind
Torsti, J.; Kocharov, L.; Anttila, A. +2 more
We present the first modeling of solar energetic particle (SEP) events inside corotating compression regions. We consider gradual compressions in the interplanetary magnetic field brought on by interaction of the solar wind streams of different speed. The compression model is similar to that previously suggested for the acceleration of low-energy …
Interplanetary and solar surface properties of coronal holes observed during solar maximum
Woch, J.; Solanki, S. K.; Forsyth, R. +2 more
Data from the Solar Wind Ion Composition Spectrometer (SWICS) on board the Ulysses spacecraft and synoptic maps from Kitt Peak are used to analyze the relatively short-lived coronal holes which exist during the maximum phase of the solar activity cycle 23. They are compared with the persistent polar coronal holes which prevail around solar minimum…
Electric field measurements in the inner magnetosphere by Cluster EDI
Baumjohann, W.; Torbert, R. B.; Matsui, H. +4 more
We report electric field measurements in the inner magnetosphere from the Electron Drift Instrument (EDI) on Cluster at distances of 4 < L < 10. The data used in this study span more than 1 year so that all local times are covered. Both components of the electric field perpendicular to the ambient magnetic field are mapped into the equatoria…
Locations of auroral kilometric radiation bursts inferred from multispacecraft wideband Cluster VLBI observations. 1: Description of technique and initial results
Gurnett, D. A.; Pickett, J. S.; Mutel, R. L. +2 more
The Cluster Wideband Data instrument has been used to determine the locations of auroral kilometric radiation (AKR) using very long baseline interferometry. The technique involves cross-correlating individual AKR bursts from all six Cluster baselines using time and frequency filtered waveforms. The resulting differential delay peaks are used to de…
Cassini plasma spectrometer measurements of Jovian bow shock structure
Dougherty, Michele K.; Gurnett, Donald A.; Coates, Andrew J. +9 more
The Cassini spacecraft on its way to Saturn flew by Jupiter and crossed its bow shock more than forty times on the dusk-side of the planet, whereas the early missions targeting Jupiter explored the dawnside. Here we report the first results concerning these bow shock crossings, based on the measurements of the Cassini Plasma Spectrometer (CAPS), t…
Cluster observations of the high-altitude cusp for northward interplanetary magnetic field: A case study
Lavraud, B.; Dunlop, M. W.; Bosqued, J. M. +7 more
Since January 2001, the multisatellite and multiinstrument CLUSTER mission gives a unique opportunity to study the structure and dynamics of the high-altitude polar cusp. On 17 March 2001, CLUSTER sampled the northern high-altitude cusp (7-9RE) around noon for more than 1 hour during very quiet interplanetary and magnetospheric conditio…
A 2.5-dimensional MHD Alfvén-wave-driven solar wind model
Habbal, S. R.; Li, X.; Hu, Y. Q.
A 2.5-dimensional MHD analysis of Alfvén-wave-driven solar wind in the heliospheric meridional plane is presented in order to extend the one-dimensional model proposed by [1967] to the two-dimensional case. In our model, no energy input is applied to the helmet streamer, while the solar wind along open field lines is assumed to be driven by Alfvén…
Launch of solar coronal mass ejections and submillimeter pulse bursts
Rovira, M.; Levato, H.; Kaufmann, Pierre +4 more
The rapid solar spikes (100-500 ms) recently discovered at submillimeter waves bring new possibilities to investigate energetic processes near the solar surface that might have an important role in the launch and propelling of ionized mass away from the Sun. We present a study on the association between the launch time of coronal mass ejections (C…