Search Publications
Three-dimensional Features of the Outer Heliosphere due to Coupling between the Interstellar and Interplanetary Magnetic Fields. IV. Solar Cycle Model Based on Ulysses Observations
McComas, D. J.; Pogorelov, N. V.; Zank, G. P. +3 more
The solar cycle has a profound influence on the solar wind (SW) interaction with the local interstellar medium (LISM) on more than one timescales. Also, there are substantial differences in individual solar cycle lengths and SW behavior within them. The presence of a slow SW belt, with a variable latitudinal extent changing within each solar cycle…
A Global Wave-driven Magnetohydrodynamic Solar Model with a Unified Treatment of Open and Closed Magnetic Field Topologies
Gombosi, T. I.; Landi, E.; Jin, M. +3 more
We describe, analyze, and validate the recently developed Alfvén Wave Solar Model, a three-dimensional global model starting from the top of the chromosphere and extending into interplanetary space (out to 1-2 AU). This model solves the extended, two-temperature magnetohydrodynamics equations coupled to a wave kinetic equation for low-frequency Al…
An Ab Initio Model for Cosmic-ray Modulation
Burger, R. A.; Engelbrecht, N. E.
A proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays (CRs) is of vital importance for a better understanding of CR modulation in the heliosphere. This study presents an ab initio model for CR modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This…
The Existence and Nature of the Interstellar Bow Shock
Ben-Jaffel, Lotfi; Grygorczuk, J.; Strumik, M. +1 more
We report a new diagnosis of two different states of the local interstellar medium (LISM) near our solar system by using a sensitivity study constrained by several distinct and complementary observations of the LISM, solar wind, and inner heliosphere. Assuming the Interstellar Boundary Explorer (IBEX) He flow parameters for the LISM, we obtain a s…
Hemispheric Asymmetries in the Polar Solar Wind Observed by Ulysses near the Minima of Solar Cycles 22 and 23
McComas, D. J.; Pogorelov, N. V.; Desai, M. I. +2 more
We examined solar wind plasma and interplanetary magnetic field (IMF) observations from Ulysses' first and third orbits to study hemispheric differences in the properties of the solar wind and IMF originating from the Sun's large polar coronal holes (PCHs) during the declining and minimum phase of solar cycles 22 and 23. We identified hemispheric …
Intervals of Radial Interplanetary Magnetic Fields at 1 AU, Their Association with Rarefaction Regions, and Their Apparent Magnetic Foot Points at the Sun
Zurbuchen, Thomas H.; Schwadron, Nathan A.; Smith, Charles W. +4 more
We have examined 226 intervals of nearly radial interplanetary magnetic field orientations at 1 AU lasting in excess of 6 hr. They are found within rarefaction regions as are the previously reported high-latitude observations. We show that these rarefactions typically do not involve high-speed wind such as that seen by Ulysses at high latitudes du…
Cross-field Diffusion of Energetic (100 keV to 2 MeV) Protons in Interplanetary Space
Tsurutani, Bruce T.; Echer, Ezequiel; Lakhina, Gurbax S. +2 more
Magnetic field magnitude decreases (MDs) are observed in several regions of the interplanetary medium. In this paper, we characterize MDs observed by the Ulysses spacecraft instrumentation over the solar south pole by using magnetic field data to obtain the empirical size, magnetic field MD, and frequency of occurrence distribution functions. The …
Current Sheet Regulation of Solar Near-relativistic Electron Injection Histories
Lario, D.; Vainio, R.; Dalla, S. +2 more
We present a sample of three large near-relativistic (>50 keV) electron events observed in 2001 by both the ACE and the Ulysses spacecraft, when Ulysses was at high-northern latitudes (>60°) and close to 2 AU. Despite the large latitudinal distance between the two spacecraft, electrons injected near the Sun reached both heliospheric location…