Search Publications
Radial evolution of nonthermal electron populations in the low-latitude solar wind: Helios, Cluster, and Ulysses Observations
Maksimovic, Milan; Štverák, Štěpán; Marsch, Eckart +3 more
We have performed a statistical study of a substantial amount of solar wind electron velocity distribution functions (eVDFs). In our data set, we combine measurements acquired onboard three spacecrafts (Helios, Cluster II, and Ulysses) in the low ecliptic latitudes covering the heliocentric distance from 0.3 up to 4 AU. In this study, we focus on …
Bulk properties of the slow and fast solar wind and interplanetary coronal mass ejections measured by Ulysses: Three polar orbits of observations
McComas, D. J.; Forsyth, R. J.; Gosling, J. T. +2 more
We examined plasma and magnetic field observations from all three Ulysses polar orbits of the Sun to study the properties of the slow and fast solar wind and interplanetary coronal mass ejections (ICMEs). We derived equations to characterize the radial and latitudinal variations for these three types of heliospheric plasma and identify distinguish…
Electron and proton heating by solar wind turbulence
Cranmer, S. R.; Matthaeus, W. H.; Kasper, J. C. +2 more
Previous formulations of heating and transport associated with strong magnetohydrodynamic (MHD) turbulence are generalized to incorporate separate internal energy equations for electrons and protons. Electron heat conduction is included. Energy is supplied by turbulent heating that affects both electrons and protons and is exchanged between them v…
Quiescent current sheets in the solar wind and origins of slow wind
Ko, Y. -K.; Moore, R. L.; von Steiger, R. +1 more
Solar wind near the heliospheric current sheet is investigated using Ulysses and ACE data in a superposed epoch analysis for several days on either side of the current sheets. Only data near sunspot minima are used, minimizing the influence of transients. New results are shown for composition and ionization state. Existing results showing a ∼2 day…
Excess open solar magnetic flux from satellite data: 1. Analysis of the third perihelion Ulysses pass
Lockwood, M.; Owens, M.; Rouillard, A. P.
We use the third perihelion pass by the Ulysses spacecraft to illustrate and investigate the “flux excess” effect, whereby open solar flux estimates from spacecraft increase with increasing heliocentric distance. We analyze the potential effects of small-scale structure in the heliospheric field (giving fluctuations in the radial component on time…
Turbulence and intermittency in the heliospheric magnetic field in fast and slow solar wind
Balogh, A.; Noullez, A.; von Steiger, R. +1 more
We study the nonuniform solar wind turbulence using high-resolution Ulysses magnetic field data measured at different solar activity level, heliospheric latitudes, and distance. We define several types of solar wind dependent of the coronal region of origin and also of the dynamical behavior of the different streams, namely, “pure” fast wind, fast…
Magnetic decrease formation from <1 AU to ∼5 AU: Corotating interaction region reverse shocks
Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L. +2 more
Magnetic decreases (MDs) have been identified and studied throughout a Ulysses fast latitude scan that lasted from 29 February 1992 to 14 September 1993. Ulysses' distance was ∼5 AU from the Sun. MDs were unbiasedly selected by application of the Interplanetary Magnetic Decrease Automatic Detection code. MDs were found to occur in high-occurrence-…
The decay phase of solar energetic particle events
Kecskeméty, K.; Daibog, E. I.; Logachev, Y. I. +1 more
The shape of the particle flux profile in the decay phase of solar energetic particle (SEP) events is of particular importance in understanding the propagation of energetic particles in the interplanetary medium. The majority of few-MeV proton events (>90%) exhibit exponential law declines, suggesting the dominant role of convection transport a…