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Latitudinal structure of the heliospheric current sheet and corotating streams measured by WIND and ULYSSES
Tsurutani, B. T.; Steinberg, J. T.; Goldstein, B. E. +5 more
All heliospheric current sheet (HCS) crossings and corotating solar wind streams detected by both WIND and Ulysses have been identified. These measurements were made when Ulysses was in its fast latitudinal scan (at a heliocentric radial distance of ∼1.4 AU) and WIND was in the ecliptic plane near the Earth. Instantaneous solar wind velocities are…
Coronal radio sounding: Non-Gaussian turbulence in the source regions of slow and fast solar wind
Pätzold, M.; Bird, M. K.; Karl, J.
Structure functions of arbitrary order are analyzed using differential phase scintillation data obtained during the fourth solar conjunction of the Ulysses spacecraft in February-March 1995. The scaling features of these structure functions clearly discriminate between electron density fluctuations observed in coronal holes versus coronal streamer…
Pick-up ions and associated wave energy transport at comet P/Halley: A case study
Neubauer, Fritz M.; Glassmeier, Karl-Heinz; Söding, Anne +1 more
During the flyby of the spacecraft Giotto at comet p/Halley Poynting vectors and Elsässer variables have been determined to study wave propagation directions. The observed wave properties are compared with the theoretically predicted RH-, LH+ and LH- wave modes. Between 10:36 and 19:11 SCET on March 13, 1986 the pr…
The Lyman-α line from the solar wind acceleration region: Results from an eight-moment approximation two-fluid solar wind model
Olsen, Espen Lyngdal
We investigate neutral hydrogen in an eight-moment, two-fluid, high speed solar wind model. In this model the proton heat flux decreases rapidly in the solar wind acceleration region, and extended coronal heating of the proton gas leads to high coronal proton temperatures and large solar wind flow speeds. The properties of the Lyman-α line from th…
Statistical acceleration of interstellar pick-up ions in co-rotating interaction regions
Schwadron, N. A.; Gloeckler, G.; Fisk, L. A.
Observations from the SWICS instrument on Ulysses reveal that there is little evidence for the acceleration of interstellar pick-up ions at the forward and reverse shocks which surround Co-rotating Interactions Regions (CIR's) in the solar wind. Rather, the pick-up ions exhibit strong acceleration in regions within the CIR where there are increase…
Limitations on suprathermal tails of electrons in the lower solar corona
Geiss, J.; Ko, Y. -K.; Gloeckler, G. +1 more
Measurements of the charge states of solar wind ions by the SWICS instrument on Ulysses are used to place limits on the extent to which the velocity distribution of electrons in the lower solar corona deviates from a Maxwellian distribution by having a suprathermal tail. It is found that the data are consistent with a suprathermal tail which is no…
The acceleration of slow coronal mass ejections in the high-speed solar wind
Riley, Pete; Gosling, J. T.
Using a one-dimensional hydrodynamic code we have simulated the radial evolution of heliospheric disturbances produced by slow coronal mass ejections (CMEs) embedded in much faster leading and trailing ambient solar wind. We find that pressure gradients induced by initial speed differences between slow CMEs and faster ambient wind can produce larg…
Latitudinal dependence of the radial IMF component: Coronal imprint
Smith, E. J.; Suess, S. T.
Measurements by Ulysses have confirmed that there is no significant gradient with respect to heliomagnetic latitude in the radial component, Br, of the interplanetary magnetic field. In the corona, the plasma β is ≪ 1, except directly above streamers, so longitudinal and latitudinal gradients in field strength will relax due to the tran…
Spatial variation of >106 Mev proton fluxes observed during the Ulysses rapid latitude scan: Ulysses COSPIN/KET results
Kunow, H.; Wibberenz, G.; Heber, B. +5 more
The basic physical processes that lead to the long-term modulation of cosmic rays in the heliosphere have been known for many years. However, our knowledge of the relative importance of the various processes is still incomplete. Observations of cosmic rays at high latitudes can be used to improve our understanding of modulation processes. In this …
Hourly variances of fluctuations in the heliospheric magnetic field out of the ecliptic plane
Balogh, A.; Horbury, T. S.; Forsyth, R. J. +1 more
Magnetic field fluctuations at high heliographic latitudes are discussed in terms of the latitude and radial dependence of their variances, as observed by the Ulysses spacecraft. The increased level of transverse fluctuations in fast solar wind flows from the polar coronal holes is similar to that found in high speed streams near the ecliptic. How…