NSSDCA ID: PSSB-00802
Availability: Archived at NSSDC, accessible from elsewhere
This description was generated automatically using input from the Planetary Data System.
Data Set Overview ================= This data set includes the time information for a given pair of sweeps, original level 2 data file, the solar wind speed proton density, proton speed, proton temperature, proton dynamic pressure, proton thermal pressure, spacecraft position and speed in Heliographic Inertial (HGI), Heliocentric Aries ecliptic, and Heliographic (Carrington) coordinates. Coverage ======== This data set specifically excludes SWAP data obtained while New Horizons was inside the Pluto system. The results provided here are for observations obtained when the solar wind beam was fully within the SWAP field of view. As explained by Heather Elliott (co-investigator): The solar wind is very radial the vast majority of the time. Since we do not have much angular information, we assume the solar wind is radial to perform our analysis. Inside the Pluto system, we have no way of knowing the direction of the ions or if we are measuring the full distribution function. We did a separate analysis for Pluto and have already published those results in McComas, et al. (2016)*, but those results to our best knowledge only reflect the portion of the distribution function that we measure and are not true density, speeds, and temperatures. Since we believe we do measure the full distribution function of the solar wind when the instrument was pointed such that the solar wind beam was well within the SWAP FOV, we refer to those results as true density, speed, and temperature. * McComas, D. J., et al. (2016), Pluto's interaction with the solar wind, Journal of Geophysical Research: Space Physics, doi:10.1002/2016JA022599. The team is planning to provide a separate archive data set for the Pluto system data because the analysis is not the same, and the quantities represented will not be the same. Processing ========== The analysis of the count rate energy distributions (SWAP level 2 data archived at PDS) to produce solar wind parameters is described by Elliott et al. (2016). This paper includes a lengthy discussion of all the calibration information used to forward model the count rate distributions, the use of Poisson errors in the fit procedure, and shows comparisons to 1 AU and Voyager 2 solar wind observations. 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. Geometric Parameter Reference Frame ----------------------------------Earth Mean Equator and Vernal Equinox of J2000 (EMEJ2000) is the inertial reference frame used to specify observational geometry items provided in the data labels. Geometric parameters are based on best available SPICE data at time of data creation. 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.
These data are available on-line from the Planetary Data System (PDS) at:
https://pdssbn.astro.umd.edu/holdings/nh-x-swap-5-derived-solarwind-v1.0/
Questions and comments about this data collection can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. David J. McComas | Data Provider | dmccomas@pppl.gov |