Search Publications
Constraints on the global structure of magnetic clouds: Transverse size and curvature
Liu, Y.; Wang, C.; Richardson, J. D. +3 more
We present direct evidence that magnetic clouds (MCs) have highly flattened and curved cross section resulting from their interaction with the ambient solar wind. Lower limits on the transverse size are obtained for three MCs observed by ACE and Ulysses from the latitudinal separation between the two spacecraft, ranging from 40° to 70°. The cross-…
Cosmic Rays at High Heliolatitudes
Potgieter, M. S.; Heber, B.
The Ulysses spacecraft has been the first to orbit the Sun over its poles and to explore the heliosphere at these high heliolatitudes. It has now completed two fast latitude scans, one at solar minimum and one at solar maximum. Since its launch in October 1990, this mission has led to several surprising discoveries concerning energetic particles, …
Current Sheet Evolution in the Aftermath of a CME Event
Raymond, J. C.; Bemporad, A.; Poletto, G. +4 more
We report on SOHO UVCS observations of the coronal restructuring following a coronal mass ejection (CME) on 2002 November 26, at the time of a SOHO-Ulysses quadrature campaign. Starting about 1.5 hr after a CME in the northwest quadrant, UVCS began taking spectra at 1.7 Rsolar, covering emission from both cool and hot plasma. Observatio…
On the Rates of Coronal Mass Ejections: Remote Solar and In Situ Observations
Cane, H. V.; Gopalswamy, N.; Richardson, I. G. +2 more
We compare the rates of coronal mass ejections (CMEs) as inferred from remote solar observations and interplanetary CMEs (ICMEs) as inferred from in situ observations at both 1 AU and Ulysses from 1996 through 2004. We also distinguish between those ICMEs that contain a magnetic cloud (MC) and those that do not. While the rates of CMEs and ICMEs t…
The Deceleration of an Interplanetary Transient from the Sun to 5 Au
Tappin, S. J.
A CME which was first seen in LASCO is tracked through SMEI and on out to Ulysses. These measurements allow us to determine the deceleration and compare different models of the deceleration process. It is found that both a simple "snow plough" model and an aerodynamic drag model predict a much more rapid deceleration in the lower solar wind than i…
Thermodynamic structure of collision-dominated expanding plasma: Heating of interplanetary coronal mass ejections
Liu, Y.; Richardson, J. D.; Kasper, J. C. +2 more
We investigate the thermodynamic structure of interplanetary coronal mass ejections (ICMEs) using combined surveys of the ejecta between 0.3 and 20 AU. ICMEs are shown to have a moderate expansion in the solar wind compared with theoretical predictions. The expansion seems to be governed by a polytrope with γ ∼ 1.3 in this distance range. We find …
Petschek-Type Reconnection Exhausts in the Solar Wind Well beyond 1 AU: Ulysses
McComas, D. J.; Forsyth, R. J.; Gosling, J. T. +2 more
We have identified 91 Petschek-type exhausts associated with local, quasi-stationary magnetic reconnection in the solar wind in plasma and magnetic field data from the Ulysses spacecraft obtained over a wide range of heliocentric distances (1.4-5.4 AU) and latitudes (S79°-N65°). The characteristic signature of an exhaust was a brief (minutes) inte…
Effect of adiabatic cooling on the fitted parallel mean free path of solar energetic particles
Zhang, M.; Qin, G.; Dwyer, J. R.
The focused transport equation without adiabatic energy loss is widely used to model solar energetic particles' (SEP) interplanetary propagation by fitting spacecraft data. We incorporate the adiabatic energy loss effect, provided by the divergence of the solar wind flows, into the focused transport equation. The equation is then solved numericall…
Heliospheric magnetic field polarity inversions driven by radial velocity field structures
Landi, Simone; Hellinger, Petr; Velli, Marco
Magnetic field polarity inversions embedded in the predominantly unipolar fast solar wind have been observed by the Ulysses spacecraft at high latitudes. Such reversals have the nature of folded back field lines which we suggest are generated by the interaction of standard large amplitude, low frequency, Alfvénic turbulence with velocity shears in…
Energetic Particle Observations
Simnett, G. M.; Lario, D.; Klecker, B. +14 more
The characteristics of solar energetic particles (SEP) as observed in interplanetary space provide fundamental information about the origin of these particles, and the acceleration and propagation processes at the Sun and in interplanetary space. Furthermore, energetic particles provide information on the development and structure of coronal mass …