PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "2017-09-29: Initial release; 20200827 RChen/EN SBN changed inLienResolutin to locallyArchived " RECORD_TYPE = STREAM INSTRUMENT_HOST_NAME = "NEW HORIZONS" OBJECT = DATA_SET DATA_SET_ID = "NH-P-SWAP-5-DERIVED-SOLARWIND-V1.0" OBJECT = DATA_SET_INFORMATION ARCHIVE_STATUS = "LOCALLY ARCHIVED" START_TIME = 2015-07-14T12:04:17 STOP_TIME = 2015-07-14T14:14:25 DATA_SET_DESC = " Data Set Overview ================= Each file of this data set includes the time information for a given pair of sweeps in the original CODMAC level 2 raw data file, the solar wind proton density, proton speed, proton temperature, proton dynamic pressure, proton thermal pressure. The Helio file of this data set has the spacecraft position in Heliographic Inertial (HGI), Heliocentric Aries Ecliptic (HAE-J2000), and Heliographic (HG). The Pluto file of this data set has the spacecraft position in Pluto J2000, Pluto IAU, and Heliographic Inertial (HGI) coordinates systems. SWAP Pluto Plasma Parameters ============================ On July 14, 2015 the Solar Wind Around Pluto (SWAP) electrostatic instrument on the New Horizons spacecraft [MCCOMASETAL2008] detected a long tail of heavy ions extending at least 100 Pluto radii from Pluto. McComas et al. 2016 describes our methods for determining the plasma parameters for those heavy ion observations; this paper should be used as the citable reference for any further use or analysis of these data. Our basic method is a numerical integration of the measured secondary count rate distribution. Heavy ions create a strong signal in the SWAP secondary detector and a weaker signal in the primary detector since the heavy ions produce a lot more secondary electrons on the side of the foil facing the secondary detector than on the primary side. Heavy ion observations were defined for any energy step where the ratio of the secondary to the primary count rate was 3.5 or greater. Energy steps where the ratio is below 3.5 have the count rate set to 0 for the heavy moments determination. The calibration information indicate that the heavy and light species are well separated at energies <3000 eV with this technique, but at energies > 3000 eV this technique does not work as well [EBERTETAL2010], [MCCOMASETAL2016]. In our analysis we assume the peak of the distribution is in the SWAP instrument field-of-view (FOV), and that the distribution is isotropic. When the spacecraft is spinning, we do not need those assumptions because the spinning of the FOV sweeps out nearly the full sky. However, the tail observations occur when the spacecraft is in 3-axis mode and not spinning. For the plasma parameters, we assume that the heavy ion species is methane (CH4) as anticipated by atmospheric models (Strobel and Zhu, 2017, and references therein) [STROBEL&ZHU2017] and indicated as being most likely in the SWAP data as show by Zirnstein et al. 2016, [ZIRNSTEINETAL2016]. The instantaneous SWAP FOV is 276 degrees by 10 degrees. We begin our analysis by assuming we fully measure the distribution within our FOV in order to estimate the number flux as first order numerical integration. Then we estimate the drift speed (vdrift) as the centroid speed of the measured count rate distribution. We use the width of the distribution to estimate the thermal speed (vth). We use both the drift speed and thermal speed to estimate the angular extent of the distribution (tan-1(vth/vdrift)). The angular extent is then used to determine the validity of our assumption that the full distribution was within the SWAP field-of-view. We find that the heavy ion distributions in the Pluto space environment do not seem to be either really hot or really cold, but instead are warm. When the distribution was wider than the SWAP FOV in either dimension, we estimate what fraction we missed and correct our estimate of the flux and density. Additionally, we correct for the motion of the spacecraft, which was moving at 13.3 km/s during this timeframe. To check the numerical integrations, we also use the cold beam analytic fitting procedure developed by Elliott et al. 2016. The only adaptations needed to the analytic Maxwellian fitting procedure were to change the mass from protons to methane and to use the effective area of the secondary detection rather than for the coincidence detection. The more complex comprehensive method by Elliott et al. 2016 requires knowing the direction of motion of the ions. Since the solar wind is typically within 1 degree of the radial direction, we can assume the solar wind is radial, but for the Pluto ions we cannot make such a simplifying assumption. Therefore, we adapted the analytic Maxwellian fitting method for the Pluto ions, which does not account for the instrument angular response rather than the comprehensive fitting procedure and consequently does not require angular information. The bulk velocities from both methods are nearly identical, especially when the counting statistics are high (i.e., times with high flux). For the density and temperature, the numerical moments calculation generally results in a higher values. This is a result of the Maxwellian not capturing the wings of the distribution. In the McComas et al. 2016 paper we show only the numerical integrations since we find the distributions to generally be a warm beam and not a cold beam as we assumed in the Maxwellian fits. Therefore, we archive the numerical integration results. Reference Frame =============== Heliographic Inertial (HGI) --------------------------- This system is Sun centered with the X-axis along the intersection line of the ecliptic (zero longitude occurs at the +X-axis) and solar equatorial planes. The Z-axis is perpendicular to the solar equator, and the Y-axis completes the right-handed system. This coordinate system is also referred to as the Heliocentric Inertial (HCI) system. Heliocentric Aries Ecliptic J2000 (HAE-J2000) --------------------------------------------- This coordinate system is heliocentric system with the Z-axis normal to the ecliptic plane and the X-axis pointes toward the first point of Aries on the Vernal Equinox, and the Y-axis completes the right-handed system. This coordinate system is also referred to as the Solar Ecliptic (SE) coordinate system. The label 'J2000' refers to the time at which one defines the Vernal Equinox. In this case it is defined at the J2000 date, which is January 1, 2000 at noon. Heliographic (HG) ----------------- This system is similar to the Heliographic Inertial one except the zero longitude is fixed on the surface of the Sun and rotates with a period of 25.38 days. Specifically, the zero was defined as the longitude at the ascending node of the equator in the ecliptic plane on January 1, 1854 at 12 UT. This system is also known as the Carrington system and is an intrinsic system to Spacecraft Planet Instrument C-matric Events (SPICE) toolkit denoted as IAU_SUN where IAU stands for International Astronomical Union. Pluto J2000 ----------- The J2000 coordinate system with the origin translated to the center of Pluto. Pluto International Astronomical Union (Pluto-IAU) -------------------------------------------------- This is a cartographic coordinate system centered on Pluto where the frame is fixed and does not move with respect to the surface of the planet. The International Astronomical Union (IAU) defines the orientation of the frame. Summary ------- The reference frames above are based on SPICE defined reference frames and central bodies. See below for a summary of their definitions in terms of SPICE. SPICE SPICE Reference Central Frame Body Description Name Name -------------------------------------------- ---- ---- Heliogr. Inertial (HGI) HCI Sun Heliocentr. Aries Eclip. J2000 (HAE-J2000) ECLIPJ2000 Sun Heliographic (HG) IAU_SUN Sun Pluto J2000 J2000 Pluto Pluto International Astronomical Union (Pluto-IAU) IAU_PLUTO Pluto Epoch of Geometric Parameters ----------------------------- All geometric parameters provided in the data labels were computed at the epoch midway between the START_TIME and STOP_TIME label fields. " ABSTRACT_DESC = " This data set presents characteristics of the solar wind derived from data taken by the New Horizons Solar Wind Around Pluto (SWAP) instrument during the Pluto encounter. This archive contains two data products. Each product compiles the CODMAC level 2 source data used, the solar wind speed, proton density, proton speed, proton temerature, proton dynamic pressure, proton thermal pressure, spacecraft position and speed. The two product files differ in that one is in Heliographic Inertial (HGI) coordinates and the other is in Pluto centric J2000 and IAU J2000 coordinates. " CITATION_DESC = " Elliott, H., Mukherjee, J., NEW HORIZONS SWAP DERIVED SOLAR WIND CHARACTERISTICS FROM THE PLUTO ENCOUNTER V1.0, NH-P-SWAP-5-DERIVED-SOLARWIND-V1.0, NASA Planetary Data System, 2018." DATA_OBJECT_TYPE = "SPREADSHEET" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_SET_NAME = " NEW HORIZONS SWAP DERIVED SOLAR WIND AT PLUTO V1.0 " DATA_SET_RELEASE_DATE = 2017-09-30 DATA_SET_TERSE_DESC = " This data set contains solar wind characteristics from the New Horizons mission during the Pluto Encounter mission phase, derived from data from the New Horizons Solar Wind Around Pluto (SWAP) instrument. " DETAILED_CATALOG_FLAG = "N" PRODUCER_FULL_NAME = "HEATHER ELLIOTT" CONFIDENCE_LEVEL_NOTE = " Every measurement in the raw dataset was used and the confidence in the final parameters is discussed in Elliott et al., 2016. [ELLIOTTETAL2016] " END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_MISSION MISSION_NAME = "NEW HORIZONS" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "ELLIOTTETAL2016" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "MCCOMASETAL2008" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "MCCOMASETAL2016" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "EBERTETAL2010" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "STROBEL&ZHU2017" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "ZIRNSTEINETAL2016" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = "SOLAR WIND" END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "NH" INSTRUMENT_ID = "SWAP" END_OBJECT = DATA_SET_HOST END_OBJECT = DATA_SET END