Search Publications
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 …
Filament eruption without coronal mass ejection
Moore, Ronald L.; Choudhary, Debi Prasad
We report characteristics of quiescent filament eruptions that were not associated with coronal mass ejections (CMEs). We examined 12 quiescent filament eruptions, each of which was located far from disk center (>=0.7 RSun) in diffuse remnant magnetic fields of decayed active regions, was well observed in full-disk movies in Hα and F…
Magnetic clouds with east/west orientated axes observed by Ulysses during solar cycle 23
Forsyth, R. J.; Rees, A.
The second Ulysses orbit of the Sun has provided a unique opportunity for the study of the interplanetary manifestation of coronal mass ejections (ICMEs) over a wide range of heliographic latitudes. The Ulysses dataset between July 1995 and mid April 2003 has been surveyed for magnetic clouds (MCs), a subset of ICMEs. As a result of the rising sol…
VLF wave activity in the solar wind and the photoelectron effect in electric field measurements: Ulysses observations
Balogh, A.; McComas, D. J.; Lin, Naiguo +2 more
We present observations of very low frequency (VLF) waves (0.2 to 448 Hz) made by Ulysses during the solar maximum and compare the observations with those obtained when the solar activity was approaching a minimum. The occurrences and properties of the waves are found to be similar during the solar maximum and solar minimum periods for slow and in…