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Interchange injection events are commonly observed by the Cassini spacecraft in the region between about 6 and 12 Rs(1 Rs= 60,268 km) and even frequently beyond. In this study, 13 examples of interchange injection events are identified in Cassini/Cassini Plasma Spectrometer data under special conditions such that time‐of‐flight (TOF) mass spectra could be obtained from entirely within the events. Using the TOF data to separate the main ion species H+, H2+, and W+, approximate densities of each species are calculated under the assumption that all distributions were isotropic. The light‐ion density ratios, H2+/H+, in the injection events are not discernibly different from those ratios in control intervals from the ambient plasma. However, the water‐group ratio, W+/H+, is significantly lower than ambient. The comparison of the measured density ratios with the range of values observed throughout Saturn's magnetosphere indicates that the values of W+/H+that are as low as those observed within the injection events are found primarily beyond L~14 (where Lis the equatorial crossing distance, in Saturn radius, of a dipole field line), indicating that the injection events are delivering plasma from the outer magnetosphere at times traveling at least 6 Rs. Ion composition (H2+/H+and W+/H+) is measured in 13 interchange injectionsW+/H+is significantly reduced compared to nearby inner magnetospheric plasmaThe composition suggests an injection origin beyond L~14

The plasma properties, especially the flow parameters, obtained from numerical integration of Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer measurements during intervals when the CAPS field of view encompassed both inward and outward flow directions relative to corotation are examined for nightside data (18–06 local time) during 2006, 2009, and 2010. The results show good agreement with previously reported values derived using different selection criteria and a different analysis technique. Nightside flows are predominantly in or near the corotation direction, indicating continuing influence of connection to the ionosphere. There is no evidence for a quasi‐steady reconnection x line within the surveyed region of the tail, although dynamic events attributable to transient reconnection have been observed. There is a net radial mass outflow, leading to an estimated net mass loss between 18 and 03 local time of ~34 kg/s. Part of this mass loss occurs as a “planetary wind” along the dusk flank. The remainder probably occurs ultimately much deeper in the tail and along the distant dawn magnetopause, when the mass disconnects from the weakened planetary magnetic field. Plasma properties in Saturn's magnetotail are reportedNightside flows are predominantly in or near the corotation directionNet radial mass outflow with estimated nightside mass loss of ~34 kg/s

At close to 2345 UT on September 24, 1998, the magnetosphere was suddenly compressed by the passage of an interplanetary shock. In order to properly interpret the magnetospheric events triggered by the arrival of this shock, we calculate the orientation of the shock, its velocity, and its estimated time of arrival at the nose of the magnetosphere. Our best fit shock normal has an orientation of (−0.981 −0.157 −0.112) in solar ecliptic coordinates, a speed of 769 km/s, and an arrival time of 2344:19 at the magnetopause at 10 RE. Since measurements of the solar wind and interplanetary magnetic field are available from multiple spacecraft, we can compare several different techniques of shock‐normal determination. Of the single spacecraft techniques the magnetic coplanarity solution is most accurate and the mixed mode solution is of lesser accuracy. Uncertainty in the timing and location of the IMP 8 spacecraft limits the accuracy of solutions using the time of arrival at the position of IMP 8.

Energetic ions (>15 keV) moving upstream from the Earth's bow shock frequently appear at the sunward Lagrangian point (L1) ∼1.5 × 106km upstream from Earth. The most common orientation of the interplanetary magnetic field (IMF) at L1 during these upstream events is near‐radial from the Sun (the nominal direction for connection to the magnetosphere). However, strong unidirectional beams of ions streaming away from Earth, consistent with good magnetic connection to the bow shock, are observed even when the IMF is transverse to the radial direction. This study includes for the first time observations of upstream events from as many as four upstream spacecraft. Included in this report are energetic ion and magnetic field measurements from (1) ACE/Electron, Proton, and Alpha Monitor (EPAM) and ACE/Magnetometer Instrument (MAG); (2) Wind/Three‐Dimensional Plasma Analyzer (3DP) and Wind/Magnetic Fields Investigation (MFI); (3) IMP 8/Energetic Particle Experiment (EPE) and IMP 8/MAG; and (4) Geotail/Energetic Particle and Ion Composition (EPIC) and Geotail/MAG. In addition, the ACE/Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) instrument identifies IMF connection between the L1 point and the Earth's bow shock by the presence of low‐energy (272‐372 eV) bidirectional electron flux. Instruments on the IMP 8 and Geotail spacecraft simultaneously measure the energetic ion intensity and IMF configuration close to the Earth's bow shock during times of particle enhancements observed at L1. Analysis of ACE, Wind, IMP 8, and Geotail observations from February through November 1998 shows that >40% of upstream events are observed during times of nonradial (>30° from the GSE Xaxis) IMF orientation. A second and independent study of ACE/EPAM observations of over 500 upstream energetic ion events from launch through November 1998 confirms this result. We find similar distributions of radial and nonradial IMF orientations both close to the bow shock and at L1. This implies that the IMF configurations during upstream events are large‐scale spatial structures with radii of curvature of the order of the Earth‐L1 distance, i.e., 0.01 AU. These spatial structures are being convected through the L1 point into the Earth's foreshock.