2.2.6 spase://CDPP/NumericalData/AMDA/MAVEN/SWIA/mav-swia-kp ions : key parameters SWIA : ions considered as protons : key parameters 2017-03-12T10:48:29Z Data follow a 4-second cadence when MAVEN is at an altitude of less than 500 km, otherwise the time cadence is 8 seconds. The in situ key parameters contain 235 parameters selected by the instrument leads and other MAVEN scientists. These data consist of values derived from L2 data provided by the in situ instruments. Principal Investigator : Jasper Halekas, Univ. Iowa, Iowa City spase://CDPP/Person/Jasper.S.Halekas PrincipalInvestigator spase://CDPP/Person/P.Dunn TechnicalContact SWIA web page, Summary sheet http://lasp.colorado.edu/home/maven/science/instrument-package/swia/ spase://SMWG/Repository/CDPP/AMDA Online Open AMDA at CDPP http://amda.cdpp.eu Text.ASCII AMDA is a science analysis system provided by the Centre de Donnees de la Physique des Plasmas (CDPP) supported by CNRS, CNES, Observatoire de Paris and Universite Paul Sabatier, Toulouse PDS /maven-insitu-calibrated spase://CDPP/Instrument/AMDA/MAVEN/SWIA ThermalPlasma 2014-10-06T00:00:00Z 2016-08-14T23:59:52Z PT4S PT8S Mars Quality flag (0 = bad, 1 = good) indicats whether the distribution is well-measured and decommutation parameters are definite. All SWIA Key Parameters are derived from onboard-computed moments. These moments are computed under the assumption that all ions are protons, and that the entire distribution is within the field of view and the energy range of the instrument. The quality flag in the KP files attempts to identify and flag those cases where a significant portion of the distribution is outside of SWIA's field of view and/or outside of the energy range of the instrument, but the computation of the quality flag is not infallible and there may still be cases where part of the distribution is missing. Meanwhile, there is no quality flag or correction for multi-ion issues. Thus, SWIA key parameter data taken inside the induced magnetospheric boundary should typically not be used for quantitative purposes. Even in the solar wind, which is ~94-97% protons, there are some values which cannot be used quantitatively, since the moments are computed over a distribution which includes not only the protons, but also ~3-6% alpha particles with twice the energy per charge. This has only a few percent effect on the density and velocity moments, so these values can safely be relied on, but even a small alpha population leads to an artificially large temperature moment (particularly the component aligned with the flow, which is often 2x or more higher than the true value). Thus, the SWIA temperature moments cannot typically be used for quantitative purposes [for qualitative purposes they may be okay in the solar wind and magnetosheath]. Those wishing to look quantitatively at solar wind temperature should use the SWIA Level 2 3-d Fine data and use appropriate routines to separately compute proton and alpha temperature. density mav_swiakp_n Total ion density from SWIA onboard moment calculation, assuming 100% protons phys.density;phys.atmol.ionStage cm-3 Ion NumberDensity v_mso mav_swiakp_vmso Bulk ion flow velocity from SWIA onboard moment calculation, assuming 100% protons phys.veloc;phys.atmol.ionStage km/s 3 vx Component 1 mav_swiakp_vmso(0) vy Component 2 mav_swiakp_vmso(1) vz Component 3 mav_swiakp_vmso(2) Ion Velocity |v| mav_swiakp_vtot Bulk ion flow velocity magnitude from SWIA onboard moment calculation, assuming 100% protons phys.veloc;phys.atmol.ionStage km/s Ion Velocity temperature mav_swiakp_t Scalar ion temperature from SWIA onboard moment calculation, assuming 100% protons phys.temperature;phys.atmol.Ionstage eV Ion Temperature dynamic pressure mav_swiakp_pdyn Ion dynamic pressure computed on the SWIA ground from density and velocity moments, assuming 100% protons phys.temperature;phys.atmol.Ionstage nPa Ion Pressure