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Electron-impact ionization of interstellar hydrogen and helium at interplanetary shocks
Isenberg, Philip A.; Feldman, William C.
We investigate the ionization of interstellar hydrogen and helium due to electron impact by shock-heated electrons. Taking the electron distributions measured at four interplanetary shocks at 1 AU, we show that the electrons in the downstream region of strong shocks can ionize interstellar atoms at rates matching or exceeding the nominal photoioni…
Potential flow downstream of the heliospheric terminal shock: A non-spherical shock
Suess, S. T.; Nerney, Steven
We have solved for the potential flow down-stream of the terminal shock of the solar wind in the limit of small departures from a spherical shock due to a latitudinal ram pressure variation in the supersonic solar wind. The solution connects anisotropic streamlines at the shock to uniform streamlines down the heliotail because we use a non-slip bo…
Heliolatitude dependence of interplanetary heavy ions
Simnett, G. M.; Lanzerotti, L. J.; Maclennan, C. G. +1 more
In its rapid traversal of 80° of heliolatitude from the southern solar pole to the equator, the HI-SCALE instrument on the Ulysses spacecraft measured the composition of ions accelerated at the co-rotating interaction regions (CIRs) that it crossed. We compare ion composition measurements as a function of heliolatitude during this traversal to tho…
Elliptically polarized bursty radio emissions from Jupiter
Kaiser, M. L.; Desch, M. D.; Stone, R. G. +3 more
We report a new component of Jovian radio emission observed by the Ulysses spacecraft when Ulysses was at high Jovigraphic latitudes (≳30° north or south of the Jovian magnetic equator). This bursty high-latitude emission is elliptically polarized in the right-hand sense when observed from northern latitudes and in the left-hand sense when observe…
Whistler-mode wave generation around interplanetary shocks in and out of the ecliptic plane
Balogh, A.; Forsyth, R. J.; Scime, E. E. +5 more
We present a study of whistler-mode wave generation and wave particle interaction in the vicinity of interplanetary shocks in and out of the ecliptic plane, as observed by the Ulysses spacecraft. We focus here on one shock in the ecliptic plane as a reference and three shocks obtained at -30, -54 and -55.4 degrees of heliographic latitude respecti…
Measurement of anomalous cosmic ray oxygen at heliolatitudes ∼25° to ∼64°
Simnett, G. M.; Pick, M.; Anderson, K. A. +8 more
We report measurements of the oxygen component (0.5 - 22 MeV/nucl) of the interplanetary cosmic ray flux as a function of heliolatitude. The measurements reported here were made with the Wart telescope of the HI-SCALE low energy particle instrument on the Ulysses spacecraft as the spacecraft climbed from ∼24° to ∼64° south solar heliolatitude duri…
Unusual wave phenomena near interplanetary shocks at high latitudes
MacDowall, R. J.; Stone, R. G.; Thejappa, G. +1 more
We report on several interplanetary shocks that are unusual because waves at about 10 Hz are highly electrostatic in the upstream region yet highly electromagnetic in the downstream region. These shocks, detected by the Unified Radio and Plasma Wave Experiment (URAP) on Ulysses are supercritical reverse shocks, which occurred predominantly at high…
Traversal of comet SL-9 through the Jovian magnetosphere and impact with Jupiter: radio upper limits
MacDowall, R. J.; Kaiser, M. L.; Desch, M. D. +2 more
Continuous radio observations below 1 MHz of Jupiter from the Ulysses spacecraft are used to establish an upper limit to the radiated power at low frequencies associated with the traversal through the magnetosphere and impact of Comet SL-9 with the planet. Although Jovian emissions were observed throughout the impact interval, no systematic intens…
Entry of galactic electrons into the high latitude heliosphere
Simnett, G. M.; Tappin, S. J.; Roelof, E. C.
Evidence is presented for the first detection of galactic cosmic ray electrons in the general energy range 1 to 20 MeV by the HI-SCALE instrument on Ulysses as it passed over the solar poles. The electrons manifest themselves by a strong latitude dependence of the background counting rates in the HI-SCALE detectors, in excess of that predicted fro…
Far-UV emissions from the SL9 impacts with Jupiter
Talavera, A.; Feldman, P. D.; Strobel, D. F. +20 more
Observations with the International Ultraviolet Explorer (IUE) during the impacts of the fragments of comet D/Shoemaker-Levy 9 with Jupiter show far-UV emissions from the impact sites within a ∼10 min time scale. Positive detections of H2 Lyman and Werner band (1230-1620 Å) and H-Lyα emissions are made for impacts K and S, and marginall…