No abstract

Bidirectional, field-aligned flows of low-energy particles in interplanetary space have been proposed as a possible signature of large-scale, looplike magnetic structures. We present the results of a survey of bidirectional anisotropy observations using data from the low-energy proton and magnetometer experiments on board ISEE 3 covering a 45-month period corresponding to the last solar maximum. During this period, 66 bidirectional flow (BDF) events have been identified, of which 48 could positively be associated with isolated magnetic field structures. We suggest that these structures are an interplanetary manifestation of coronal mass ejection (CME) events, and are able to group the BDF events into five classes according to the field signature of the related magnetic structure and the association or otherwise with an interplanetary shock. We conclude that the BDF events are an interplanetary signature not only of energetic, flare-associated transients but also low energy, nonflare CMEs. From a comparison of anisotropy signatures at 35 and 620 keV we conclude that our observations are most consistent with the transient magnetic structures being detached bubbles comprising closed loops or tightly wound cylindrical helices rather than extended tonguelike loops attached to the Sun at the time of observation. , 1984, 1986Schwenn, 1986]. In particular, the interplanetary signatures of energetic, flare-initiated CMEs have been widely studied, resulting in a general acceptance of the idea that most, if not all, interplanetary shock waves are produced by CME events. Evidence exists, however, that such energetic CME events are only a small fraction, perhaps 10% or less, of the total CME population [Gosling et al., 1974;Newkirk et al., 1981]. This idea is supported by the results of a study by Klein and Burlaga [1982] of so-called magnetic clouds, thought to be the magnetically contained ejecta from CMEs, in which they showed that only ca. one third of the 45 clouds identified had a positive shock association. Sime and Hundhausen [1987], in a study of looplike CMEs identified in SMM coronograph data, have analysed an event which they propose as a candidate for a coronal shock. They emphasize, however, that the event in question is atypical for the data set, and that the majority of SMM looplike CMEs cannot be identified with a shock front. In spite of the large body of correlative data linking CMEs observed close to the Sun to a range of interplanetary phenomena, detailed information is still lacking regarding the development of CMEs between the point at which they leave the field of view of space-borne coronagraphs and their detection in-situ by spacecraft in interplanetary space. Of particular importance in this respect is the magnetic field configurafion. The looplike topology seen in many coronagraph images of CMEs has been the basis for suggesting that at-tached, closed magnetic "bottles" could expand out to 1 AU and beyond in the manner proposed originally by Gold [1959]. On the other hand, as originally pointed out...

The Ulysses spacecraft made the first exploration of the region of Jupiter's magnetosphere at high Jovigraphic latitudes ( approximately 37 degrees south) on the dusk side and reached higher magnetic latitudes ( approximately 49 degrees north) on the day side than any previous mission to Jupiter. The cosmic and solar particle investigations (COSPIN) instrumentation achieved a remarkably well integrated set of observations of energetic charged particles in the energy ranges of approximately 1 to 170 megaelectron volts for electrons and 0.3 to 20 megaelectron volts for protons and heavier nuclei. The new findings include (i) an apparent polar cap region in the northern hemisphere in which energetic charged particles following Jovian magnetic field lines may have direct access to the interplanetary medium, (ii) high-energy electron bursts (rise times approximately 17 megaelectron volts) on the dusk side that are apparently associated with field-aligned currents and radio burst emissions, (iii) persistence of the global 10-hour relativistic electron "clock" phenomenon throughout Jupiter's magnetosphere, (iv) on the basis of charged-particle measurements, apparent dragging of magnetic field lines at large radii in the dusk sector toward the tail, and (v) consistent outflow of megaelectron volt electrons and large-scale departures from corotation for nucleons.

Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.