Search Publications
Solar Wind Corotating Stream Interaction Regions Out of the Ecliptic Plane: ULYSSES
McComas, D. J.; Goldstein, B. E.; Bame, S. J. +4 more
Ulysses plasma observations reveal that the forward shocks that commonly bound the leading edges of corotating interaction regions (CIRs) beyond ∼2 AU from the Sun at low heliographic latitudes nearly disappeared at a latitude of S26°. On the other hand, the reverse shocks that commonly bound the trailing edges of the CIRs were observed regularly …
Further Studies of Waves Accompanying the Solar Wind Pick-up of Interstellar Hydrogen
Balogh, A.; Tsurutani, B. T.; Smith, E. J. +2 more
Data collected by the magnetometer onboard the Ulysses spacecraft are surveyed for the occurrence of waves generated during the pick-up of interstellar hydrogen. Thirty one wave events were found during a 640 day study period, between March 21, 1992 and December 20, 1993 (after the Ulysses encounter with Jupiter). It is found that observation of t…
ULYSSES Out-of-Ecliptic Observations of ``27-day'' Variations in High Energy Cosmic Ray Intensity
Balogh, A.; Simpson, J. A.; McKibben, R. B. +2 more
We report the discovery that for latitudes above ∼40°S, the observed recurring modulation of cosmic rays and anomalous nuclei occurs without the detection byUlysses of the solar wind velocity and magnetic field recurring enhancements that have, heretofore at lower latitudes, defined corotating interaction regions—i.e., the mechanism producing the …
High energy cosmic-ray nuclei results on Ulysses: 2. Effects of a recurrent high-speed stream from the southern polar coronal hole
Sierks, H.; Kunow, H.; Wibberenz, G. +9 more
Since June 1992 the Kiel Electron Telescope on board ULYSSES measures 26-day variations of the order of 6% in the fluxes of high energy H and He. In May 1993 ULYSSES entered into the unipolar region of the southern polar coronal hole, but continued to observe similar effects: increases in the MeV proton channels due to acceleration near the shocks…
Solar wind helium isotopic composition from SWICS/ULYSSES
Bochsler, P.; Geiss, J.; Gloeckler, G. +2 more
This is the first study of the isotopic composition of solar wind helium with the SWICS time-of flight mass spectrometer. Although the design of SWICS is not optimized to measure3He abundances precisely,4He/3He flux ratios can be deduced from the data. The long term ratio is 2290±200, which agrees with the results …
Ulysses solar wind observations to 56° south
McComas, D. J.; Goldstein, B. E.; Bame, S. J. +3 more
In the 25 months since Jupiter flyby, the Ulysses spacecraft has climbed southward to a heliolatitude of 56°. This transit has been marked by an evolution from slow, dense coronal streamer belt solar wind through two regions where the rotation of the Sun carried Ulysses back and forth between streamer belt and polar coronal hole flows, and finally…
Co-rotating Particle Enhancements Out of the Ecliptic Plane
Simnett, G. M.; Tappin, S. J.; Roelof, E. C. +1 more
The characteristics of the recurrent electron (38 53 keV) and ion (>∼0.5 MeV) enhancements observed by Ulysses from mid-1992 to April 1994 are presented. The magnitude of the ion flux increases reached a maximum at a latitude of ∼20°S and decreased afterwards by ∼23%/degree until early 1994. The magnitude of the electron increases showed a simi…
Three-DImensional Cosmic-Ray Simulations: Heliographic Latitude and Current-Sheet Tilt
Jokipii, J. R.; Kóta, J.
We present the results from a study of the variations of the cosmic-ray intensity with time, heliographic latitude, and longitude, and for varying interplanetary conditions, using our three-dimensional, time-dependent computer code for cosmic-ray transport in the heliosphere. Our code also produces a solar-wind and interplanetary magnetic field (I…
Cosmic Ray Modulation in the 3-D Heliosphere
Simpson, J. A.; McKibben, R. B.; Zhang, M. +2 more
The basic physical processes that lead to the long-term modulation of cosmic rays by the solar wind have been known for many years. However our knowledge of the structure of the heliosphere, which determines which processes are most important for the modulation, and of the variation of this structure with time and solar activity level is still inc…
SPARTAN 201 Coronal Spectroscopy During the Polar Passes of ULYSSES
Guhathakurta, M.; Strachan, L.; Kohl, J. L. +2 more
Spartan 201 is a shuttle deployed spacecraft that is scheduled to perform ultraviolet spectroscopy and white light polarimetry of the extended solar corona during two 40 hour missions to occur in September 1994 and August 1995. The spectroscopy is done with an ultraviolet coronal spectrometer which measures the intensity and spectral line profile …