PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2006-12-27 SOC:Carcich Initial version; " RECORD_TYPE = STREAM OBJECT = INSTRUMENT INSTRUMENT_HOST_ID = "NH" INSTRUMENT_ID = "SWAP" OBJECT = INSTRUMENT_INFORMATION INSTRUMENT_NAME = "SOLAR WIND AROUND PLUTO" INSTRUMENT_TYPE = "PLASMA INSTRUMENT" INSTRUMENT_DESC = " ######################################################################## ######################################################################## REQUIRED READING: - McComas et al. (2007) [MCCOMASETAL2007] - Weaver et al. (2007) [WEAVERETAL2007] ######################################################################## ######################################################################## The SWAP description was was adapted from the New Horizons website, Weaver et al. (2007) [WEAVERETAL2007], and McComas et al. (2007) [MCCOMASETAL2007]. Instrument Overview ======== Specifications -------- NAME: SWAP (Solar Wind Around Pluto) DESCRIPTION: Low energy plasma instrument PRINCIPAL INVESTIGATOR: Dave McComas, SwRI ENERGY RANGE: 30 eV - 7.7 keV FIELD OF VIEW: 270 deg x 10 deg (Note 1) ANGULAR RESOLUTION: N/A ENERGY RESOLUTION: 1eV (<2keV); 9% (>2 keV) Note 1: deflection angles up to +15 deg additional Description -------- Solar Wind Around Pluto (SWAP) instrument is designed to measure the properties of solar wind ions for the New Horizons mission to Pluto. The SWAP instrument is an electrostatic instrument. The SWAP electro-optics control the energy band pass of ions entering the instrument. The electro-optics has three parts: the Retarding Potential Analyzer (RPA), the Electrostatic Analyzer (ESA), and the deflector (DFL). The RPA consists of four grids with the inner two having a positive voltage, which repels ions with energies less than the corresponding potential energy (qV). The Electrostatic Analyzer has two parts, which are concentrically spaced, an inner dome and an outer spherical shell (at ground). Only ions with a limited range of energies pass through the ESA to reach the detector. The deflector is used to adjust the field of view. Scientific Objective ======== The Solar Wind Analyzer around Pluto (SWAP) instrument will measure charged particles from the solar wind near Pluto to determine whether Pluto has a magnetosphere and how fast its atmosphere is escaping. Calibration ======== See /DOCUMENT/SWAP/SWAP_CAL.* and Section 4 of McComas et al. (2007) [MCCOMASETAL2007], also available as a preprint at this URL: http://www.boulder.swri.edu/pkb/ssr/ssr-swap.pdf as of 20.April, 2007. Operational Considerations ======== SWAP data are affected by spacecraft attitude and thruster firings. Values for those parameters concurrent with each observation, along with housekeeping information, are included in the observation's data file. The SWAP experiment detects atmospheric escape from Pluto as a change in the solar wind caused by the interaction of the Pluto atmosphere with the solar wind. In certain scenarios, a factor of 10 variation in the solar wind may occur over a period of days. It is therefore critical to measure the solar wind for several solar rotations in order to characterize the most likely external solar wind properties during the actual encounter period. Detectors & Electronics ======== See the instrument description and specifications above. Operational Modes ======== See Tables IV & V in the Space Science Reviews paper McComas et al. (2007) [MCCOMASETAL2007], also available as a preprint at this URL: http://www.boulder.swri.edu/pkb/ssr/ssr-swap.pdf Measured Parameters ======== SWAP counts events which represent the interactions between the SWAP electro-optics and solar wind particles. The energy of any detected event is determined by the energy bandpass in effect at the time of that event, which in turn is determined by the ESA and RPA settings (voltages). SWAP sweeps its energy bandpass over the instrument's energy range, sorts events into energy and time bins, and returns either real-time science or summary data based on those events. Indirectly through calibration, the SWAP instrument measures the bulk properties of the solar wind (speed, density, temperature), and analysis of changes in these parameters during Pluto encounter will provide an indication of the nature of any atmospheric particles that are escaping Pluto. See the SWAP SSR paper for more detail. " END_OBJECT = INSTRUMENT_INFORMATION OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "MCCOMASETAL2007" END_OBJECT = INSTRUMENT_REFERENCE_INFO OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "WEAVERETAL2007" END_OBJECT = INSTRUMENT_REFERENCE_INFO END_OBJECT = INSTRUMENT END