Search Publications
Remote Sensing of H from Ulysses and Galileo
McComas, D.; Witte, M.; Pryor, W. +5 more
We model interplanetary H Lyman-α (Lα) observations from Galileo UVS (Ultraviolet Spectrometer) and EUVS (Extreme Ultraviolet Spectrometer) (Hord et al., 1992) and the Ulysses interstellar neutral gas (GAS) instrument (Witte et al., 1992). EUVS measurements near solar maximum (max) in 1990 1992 have a peaked brightness maximum upwind due to a rath…
Ion Acoustic Waves in the Heliosphere
Lin, Naiguo; Kellogg, P. J.; MacDowall, R. J. +1 more
Observations of ion acoustic waves in the solar wind during the first and second orbit of the Ulysses spacecraft are presented. The observations show variations of the wave activity with the heliolatitude and with the phase of the solar cycle. The interrelationships between the wave intensity and the electron heat flux and the ratio of electron to…
An Estimate of Drift Effects in Various Models of the Heliospheric Magnetic Field
Potgieter, M. S.; Burger, R. A.; van Niekerk, Y.
We use a comparison with other models to estimate how significant drifts will be in the Fisk model of the heliospheric magnetic field (HMF). We also show that drifts are still be present in an idealized field model for the period shortly after the solar polarity reversal.
Cosmic Ray Transport in a Heliospheric Magnetic Field with Non-Polar Coronal Holes
Jokipii, J. R.; Kóta, J.
The simple tilted dipole picture of Corotating Interaction Regions which prevailed during the first polar pass of Ulysses no longer applies since the Sun entered a more active phase. Recent observations show that CIRs still persist, though the large polar coronal holes of solar minimum shrink to smaller areas and move to lower latitudes. We presen…
Latitudinal Variation of the Underlying Heliospheric Magnetic Field Direction: Comparison of the Ulysses First and Second Orbits
Balogh, A.; Forsyth, R. J.; Smith, E. J.
We discuss the underlying direction of the heliospheric magnetic field measured by Ulysses in the latitude range 6° S-65° S by examining distributions of the magnetic field azimuthal angle with respect to the simple Parker spiral model. During the first Ulysses traversal of this latitude range in 1992 1994, while solar activity was declining, the …
26-day Analysis of Energetic Ion Observations at High and Low Heliolatitudes: Ulysses and ACE
Lario, D.; Forsyth, R. J.; Roelof, E. C. +1 more
We present observations of energetic (0.34 8 MeV) ions from the Ulysses spacecraft during its second ascent to southern high latitude regions of the heliosphere. We cover the period from January 1999 until mid-2000 as Ulysses moved from 5.2 AU and 18° S to 3.5 AU and 55° S. In contrast to the long-lived and well-defined ∼26-day recurrences that we…
Magnetic Field Observations of Transient Events at Ulysses, 1996 2000
Balogh, A.; Forsyth, R. J.; Smith, E. J. +1 more
During the years 1996 2000 solar activity has been gradually rising and is now close to maximum. At the same time the Ulysses spacecraft has performed a north to south traverse of the low latitude regions of the heliosphere and is now once again travelling through high southerly latitudes. We show some examples and report on the occurence rates of…
Planar Structuring of Magnetic Fields at Solar Minimum and Maximum
Balogh, André; Jones, Geraint H.
Planar magnetic structures are regions of the solar wind where the magnetic field is oriented parallel to a fixed plane for several hours or more. Discontinuities in the field direction may be encountered during these periods, their surfaces also being parallel to the plane containing the field. A survey of Ulysses magnetic field data returned dur…
The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures
Suess, S.; Poletto, G.
SOHO-Ulysses quadrature occurs when their included angle with the Sun is 90°. At these times the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO and then later be sampled in situ at Ulysses. Quadratures in Fall 2000/2001 are of special interest because Ulysses will be near the south and north heliog…
Dust Properties in the Local Interstellar Medium
Kimura, Hiroshi; Mann, Ingrid
Ulysses measurements yield reliable in-situdetection of large dust particles which stem from the interstellar medium (ISM) and which are not observed in interstellar extinction data. Both current models of large grains in the ISM: core-mantle grains as well as composite grains, are in agreement with dust properties implied by the Ulysses results. …