Search Publications
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…
Thermal anisotropies in the solar wind: Evidence of heating by interstellar pickup ions?
Phillips, John L.; Richardson, John D.; Smith, Charles W. +1 more
A recent paper by Gray et al. [1996] shows that the Alfvén ion cyclotron instability is generated by newly created pickup ions and heats the thermal solar wind protons in the direction perpendicular to the magnetic field. This instability operates most effectively in regions where the plasma β is low, so this mechanism predicts that the ratio of t…
Observations of a sky Lyman α groove related to enhanced solar wind mass flux in the neutral sheet
Bertaux, Jean-Loup; Lallement, Rosine; Quémerais, Eric
We report several observations of the Lα interplanetary emission recorded by a photometer flown in 1977 on board the soviet spacecraft Prognoz-5. The Prognoz scans sampled emission in a plane perpendicular to the sun-spacecraft line and also traversed the Lα maximum emission region (MER), a region centered a few AU from the Sun on the upstream int…
Interstellar pickup H+ Ions at 8.3 AU: Pioneer 10 plasma and magnetic field analyses
Intriligator, Devrie S.; Siscoe, George L.; Miller, W. David
Analysis of Pioneer 10 plasma and magnetic field observations at 8.3 AU in 1975 provides new evidence for the presence of interstellar pickup hydrogen (H+) ions. Use of plasma sensors that look far from the solar wind direction confirms the spherical shell distribution of the pickup ions in velocity space. Phase space density and flux e…
Type III bursts observed simultaneously by Wind and Ulysses
Bougeret, J. -L.; Hoang, S.; Leblanc, Y. +1 more
We consider a period of five months when Ulysses was passing behind the Sun as viewed from Wind and measure the low frequency cutoffs flo and the local plasma frequency fp for 303 bursts seen by one, the other, or both spacecraft. The preliminary results are: 1) 68% of the bursts were seen on dynamic spectra of both spacecraf…