Search Publications
Bow shock motions observed with CLUSTER
André, M.; Maksimovic, M.; Bale, S. D. +1 more
The Cluster mission allows the determination not only of the bow shock crossing position but also, with a simple timing method and a reasonable confidence, the shock normal and the velocity along this normal. We apply this technique to a series of eleven consecutive bow shock crossings which occurred during a time interval of approximatively two a…
Are CME ``interactions'' really important for accelerating major solar energetic particle events?
Szabo, Adam; Richardson, Ian G.; Haggerty, Dennis K. +2 more
Recent studies have proposed that the presence or absence of an ``interaction'' with a preceding coronal mass ejection (CME) or other coronal structure within ~50 Rs of the Sun discriminates large, fast CMEs associated with major solar energetic particle (SEP) events from those that are not. We conclude that there is no compelling evide…
Solar magnetic field reversal as seen at Ulysses
Balogh, André; Smith, Edward J.; Jones, Geraint H.
The rapid motion of the Ulysses spacecraft from high southern to high northern latitudes in 2000-2001 provided an excellent opportunity to make inferences regarding the solar magnetic dipole's behaviour around solar maximum. A simple dipole model is fitted to Ulysses measurements of the polarity of the heliospheric magnetic field mapped back to th…
What high altitude observations tell us about the auroral acceleration: A Cluster/DMSP conjunction
Janhunen, P.; Wahlund, J. -E.; Winningham, D. +10 more
Magnetic conjugate observations by Cluster and DMSP F14 satellites are used to study the field lines of auroral arc. Cluster is well above the acceleration region and observes upward keV ion beams and bipolar electric structures. The integrated potential at Cluster altitudes shows a dip that is consistent with the keV electron acceleration energy …
Propagation of energetic particles in the high-latitude high-speed solar wind
Dalla, S.; Forsyth, R. J.; Gosling, J. T. +4 more
We present observations of energetic particles in the energy range ~1 MeV to ~100 MeV made by the COSPIN instrument on board the Ulysses spacecraft during the recent second northern polar pass. For a short time during this pass the Ulysses spacecraft was at high heliographic latitude, above the current sheet, and immersed in high-speed solar-wind …
Heliospheric ``FALTS'': Favored Acceleration Locations at the Termination Shock
McComas, D. J.; Schwadron, N. A.
The standard explanation for Anomalous Cosmic Rays requires strong energization at the heliospheric termination shock. However, the tightly wrapped magnetic spiral in the outer heliosphere produces a quasi-perpendicular shock where it is difficult to accelerate low energy particles. We show that motion of footpoints between regions of fast and slo…
Observations of auroral broadband emissions by CLUSTER
Balogh, A.; Wahlund, J. -E.; Winningham, D. +16 more
We present the results of a study based on several events of broadband ULF/ELF emissions observed in the auroral region by the CLUSTER multi-spacecraft at distances around 4-5 RE. These emissions, observed below the ion plasma frequency, are similar to the broadband emissions observed at lower altitudes (800-4000 km) by rockets (e.g. AM…
Plane-of-sky simulations of interplanetary shock waves
Dryer, M.; Smith, Z.; Fry, C. D. +3 more
We present simulated plane-of-sky maps of the shock waves in interplanetary space from several representative solar events by using the Hakamada-Akasofu-Fry solar wind model (HAFv.2). This kinematic model uses a three-dimensional approach to construct plane-of-sky maps of interplanetary shock waves initiated by solar flares and CMEs. The simulated…
Evolution of the galactic cosmic ray electron to proton ratio: Ulysses COSPIN/KET observations
Kunow, H.; Ferreira, S. E. S.; Potgieter, M. S. +3 more
The Ulysses orbit provides a unique opportunity to study the propagation of cosmic rays in a wide range of heliographic latitudes and during different solar activity and polarity in the inner heliosphere. Around July 2000 the solar magnetic field reversed its global polarity. In late 2000, the electron to proton ratio at the rigidities of 1.2 GV a…
Sharp boundary between the inner magnetosphere and active outer plasma sheet
Sauvaud, J. -A.; Balogh, A.; Zong, Q. -G. +6 more
We report observations of a sharp spatial boundary between the outer plasma sheet and the inner magnetosphere. It was successively crossed by the Cluster spacecraft in their pearl-on-string configuration near the perigee (~4 Re) at midnight during a substorm expansion phase. Being mapped presumably to 8-10 Re in the equatorial tail, this boundary …