A comparative study of upstreaming energetic ions in the kilovolt energy range and electrostatic hydrogen cyclotron (EHC) waves has been made using the ion mass spectrometer and plasma wave receiver data sets for the first 1200 orbits of the S3‐3 spacecraft. The upstreaming energetic ions and EHC waves are found to coincide in over 90% of the events studied. In addition, both EHC waves and upstreaming ions with energies greater than 500 eV exhibit a lower border in their altitude distribution near 5000 km. The nearly exact correlation suggests either that the upstreaming ions are producing the EHC waves or that the EHC waves are heating the ions. One example of EHC waves and upstreaming energetic ions is analyzed to test the two hypotheses. Evidence that EHC waves are heating ions is presented in the form of conic ion distributions which some theories predict are the consequence of this process. Perpendicular ion heating to at least 6 keV is found to coincide with EHC waves. Evidence that the upstreaming ions are the source of free energy for the EHC waves is presented in the form of an ion distribution function with ∂f/∂ν > 0. However, the stability of that ion distribution function is considered and found to be stable unless other conditions such as filamentation or electron drift are invoked. There also exists the possibility that the source of free energy for EHC waves is drifting thermal electrons. For the one example studied the drifting electron process is consistent with data from the S3‐3 magnetometer. However, it is inconsistent with the S3‐3 electron spectrometer which indicates that the current is carried by keV electrons, not thermal electrons. Consequently, the source of free energy for EHC waves is not yet unambiguously determined.

Measurements from electrostatic analyzers aboard the polar-orbiting S3-3 satellite have been tabulated to form a synoptic picture of the occurrence of upgoing 90eV to 3.9keV auroral ions. In this survey, a distinction is made between ion distributions having peak fluxes along B (beams) and those exhibiting flux maxima that are not field-aligned (conics). It is shown that both beams and conics are common auroral phenomena, whose frequencies of occurrence in latitude, local time, and altitude have a marked dependence on magnetic activity. During quiet conditions (Kp • 3) conical ion distributions are observed with constant frequency in altitude above 1000 km and appear to be associated with the daytime polar cusp region. In contrast, quiet time ion beams have a maximum occurrence frequency in the premidnight sector. Ion beams are observed primarily above 5000 km, with a frequency increasing with altitude up to the satellite apogee at 8000 km. During disturbed times, ion beams are a persistent phenomenon, mainly confined to the dusk sector, while conical distributions are observed uniformly in local time with a frequency that increases steadily in altitude. The results of this study, which are shown to be consistent with previous surveys of upward flowing ions if no distinction is made between conical and field-aligned distributions, provide information relating to auroral ion acceleration processes.

Measurements of high altitude ((1.3 R•o) ions and electrons at auroral energies are used provide evidence of parallel electric field acceleration over the dusk to midnight auroral regions for both the north and south hemispheres. The data, taken on August 1Z, 1976 by charged particle spectrometers on tl•-e' S3-3 satellite, show evidence of potential differences of ~Z kV below and ~1 kV above a satellite altitude of 7300 km. Introduction The study of the coupling between the magnetosphere and the ionosphere remains one of the most actively pursued subjects in space sciences. In the auroral regions, electric fields play a dominant role in the deSCription of the dynamics of charged particles (Banks, 1975). One such result of the predicted parallel electric fields are the inverted 'V' structures widely discussed by Frank (1975), (Frank and Ackerson 1971, 197Z), Gurnett (197Z) and others (Reasoner and Chappell, 1973). Another signature of parallel electric fields that extend down to the ionosphere are ion beams accelerated to high altitudes (Shelley et al. 1976). The S3-3 satellite has provided evidence of strong electric fields which are ascribed as electrostatic shocks by Mozer et al., (1976). The data presented in this letter, taken by the S3-3 satellite on August 1Z, 1976, Provides convincing evidence of the acceleration of particles by electric fields parallel to B above and below a satellite altitude of 7300 kin. For this particula r event, a total potential difference of ~ 3 kV is inferred,. Z/3 of which is located below the satellite. Instrumentation The data were obtained bytwo cylindrical electrostatic analyzers (ESAs) built byThe Aerospace Corporation and flown on the polar ørbiting satellite, S3-3. The nominal orbital parameters were: apogee of •8040 kin, perigee of -• 240 kin' inclinatio n of 97.5 ø. The ESA's measured ions with energy to charge ratios in the range of 0.09 to 3.9 keV/q and electrons with energies of 0.17 to 8.4 keV in eight logarithmic steps. A COmplete ion and electron Spectrum was taken every seCOnd and a complete angular distribution was me_• sUred every .•0 se$-' The •metric factors of 1.8 x 10and 1.7 x 10 -• cm--ster--•--•. -for the ions and electrons r•ectively give the ins•'rument high sensitivity with low background signals. The angular fields of view were ~7 ø x 10 'ø FWHM and ~14 ø x 10 ø FwHM for the electron and ion ESA respectively. Channeltrons were used as detectors with a post acceleration to 1.6 kV in the ion ESA. A companion instrument provides measurements of electrons and protons with energies from 0.01Z to 1.6 MeV and 0.080 to 1.5 MeV respectively.

Charged particle data taken by the S3‐3 satellite, reported by Mizera and Fennell (1977), are presented as contours of the velocity distribution function on a velocity‐space diagram. This report focuses on the analytical technique used to interpret the particle data. Details of features exhibited by the electron and ion data in the velocity‐space representations are discussed in terms of a simple electrostatic acceleration model. The observed particle populations are separated in velocity‐space by recognizable demarcations calculated from the conservation laws in accordance with Liouville's theorem.

Variable intensities of geomagnetically trapped protons with energies between 12.4 and 500 key were observed during times encompassing the magnetic storms on March 20 and 24, 1969. These proton fluxes were measured for 1.0 < L < 1.1 near the magnetic equator at local midnight with solid state detectors and an electrostatic analyzer on the low-altitude satellite OV1-17. Marked increases of proton intensities at energies below 100 kev occurred during this magnetically disturbed period. In contrast, proton intensities with E > 200 kev were observed to be a relatively stable and permanent feature of this region of the near-earth magnetosphere. The altitude range for these measurements was 400-470 kin, a region where the atmospheric density is such that charge exchange lifetimes are comparable with the bounce period and short in relation to the longitudinal drift period. The OV1-17 observations of proton intensities with E > 200 kev are in substantial agreement with similar measurements taken with the Azur satellite and reported recently by Moritz (1972). Further, the lower-energy proton intensities, measured with OV1-17 instrumentation, support Moritz's suggestion that the source of these low-altitude protons is the ring current.