File Naming Format: psp_swp_spc_l3i_YYYYMMDD_v01.cdf
This data product contains derived measurements of ion properties in the solar wind, including those for density, temperature, and velocity. These are determined both by a direct computation of the velocity moments of the reduced distribution function and by attempting to fit the primary peak in the ion I(V) curve with a Maxwellian model. These measurements correspond one to one with spectra in the psp_swp_spc_l2i file for the same date. It may be convenient for some applications to cross-reference the two. For example, the corresponding l3i file contains ephemeris and data quality flag information that may be useful for an investigator who is concerned only with l2i type measurements.
Conditions that impact measurement quality are documented in the DQF variable, which contains a 32 element flag array for each measurement time. Each element of the array is reserved to signify a specific condition. These conditions are described in the DQF_FLAGNAMES variable. In this version, for example, DQF_FLAGNAMES.DAT[23] is set to "spacecraft maneuver". If measurement "i" was made during a spacecraft maneuver, it is thus flagged with DQF.DAT[23,i] = 1.
In Version 01, measurements are not provided, i.e. variables are set to fill, during spacecraft maneuvers, under conditions of low signal-to-noise, and during certain observed transients. Such conditions are rare during encounters, but increasingly frequent in interplanetary cruise. These conditions are documented in the DQF variable. Remarks are also provided in the "SPC Reduced Data Quality Periods" table. In Version 01, the solar wind alpha particle component is not measured. Thus, variables are set equal to fill values.
Data quality is very good for the duration of the encounter. The solar wind flow was within the optimal field of view for the SPC instrument for nearly the entire encounter. See the data flags for specific exceptions. As with all encounters, signal-to-noise is higher during ingress than egress, which is reflected in the typically smaller uncertainties and less frequent "primary peak low signal" flag events.
Measurements recorded during cruise phase are not all transmitted to Earth. The typical return is one spectrum out of every 32.
Due to an erroneous setting in the operating mode for this encounter, ion full scan spectra and certain spectra immediately following ion full scans are of reduced quality. In the affected full scan spectra, the energy steps over an initial portion of the measurement spectra have zero width, i.e. the Level 2 ion variables MV_LO.DAT = MV_HI.DAT, and the corresponding measurements are purely noise. In some cases, this results in a poor determination of the proton "primary peak" energy, which renders additional subsequent full scans that follow subject to the same incompleteness. In other cases, the energy range for the subsequent "ion peak tracking mode" scan is not ideal. The affected Level 3 ion measurements have been flagged with DQF.DAT[22]=1, which stands for "energy ranging/peak tracking error" and/or set to fill. The operating mode has been revised such that future encounters will not be so affected.
As part of the development of collaboration with the broader Heliophysics community, the mission has drafted a "Rules of the Road" to govern how PSP instrument data are to be used.
Version:2.3.1
File Naming Format: psp_swp_spc_l3i_YYYYMMDD_v01.cdf
This data product contains derived measurements of ion properties in the solar wind, including those for density, temperature, and velocity. These are determined both by a direct computation of the velocity moments of the reduced distribution function and by attempting to fit the primary peak in the ion I(V) curve with a Maxwellian model. These measurements correspond one to one with spectra in the psp_swp_spc_l2i file for the same date. It may be convenient for some applications to cross-reference the two. For example, the corresponding l3i file contains ephemeris and data quality flag information that may be useful for an investigator who is concerned only with l2i type measurements.
Conditions that impact measurement quality are documented in the DQF variable, which contains a 32 element flag array for each measurement time. Each element of the array is reserved to signify a specific condition. These conditions are described in the DQF_FLAGNAMES variable. In this version, for example, DQF_FLAGNAMES.DAT[23] is set to "spacecraft maneuver". If measurement "i" was made during a spacecraft maneuver, it is thus flagged with DQF.DAT[23,i] = 1.
In Version 01, measurements are not provided, i.e. variables are set to fill, during spacecraft maneuvers, under conditions of low signal-to-noise, and during certain observed transients. Such conditions are rare during encounters, but increasingly frequent in interplanetary cruise. These conditions are documented in the DQF variable. Remarks are also provided in the "SPC Reduced Data Quality Periods" table. In Version 01, the solar wind alpha particle component is not measured. Thus, variables are set equal to fill values.
Data quality is very good for the duration of the encounter. The solar wind flow was within the optimal field of view for the SPC instrument for nearly the entire encounter. See the data flags for specific exceptions. As with all encounters, signal-to-noise is higher during ingress than egress, which is reflected in the typically smaller uncertainties and less frequent "primary peak low signal" flag events.
Measurements recorded during cruise phase are not all transmitted to Earth. The typical return is one spectrum out of every 32.
Due to an erroneous setting in the operating mode for this encounter, ion full scan spectra and certain spectra immediately following ion full scans are of reduced quality. In the affected full scan spectra, the energy steps over an initial portion of the measurement spectra have zero width, i.e. the Level 2 ion variables MV_LO.DAT = MV_HI.DAT, and the corresponding measurements are purely noise. In some cases, this results in a poor determination of the proton "primary peak" energy, which renders additional subsequent full scans that follow subject to the same incompleteness. In other cases, the energy range for the subsequent "ion peak tracking mode" scan is not ideal. The affected Level 3 ion measurements have been flagged with DQF.DAT[22]=1, which stands for "energy ranging/peak tracking error" and/or set to fill. The operating mode has been revised such that future encounters will not be so affected.
As part of the development of collaboration with the broader Heliophysics community, the mission has drafted a "Rules of the Road" to govern how PSP instrument data are to be used.
| Role | Person | |
|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Justin.C.Kasper |
| 2. | MetadataContact | spase://SMWG/Person/Robert.M.Candey |
| 3. | MetadataContact | spase://SMWG/Person/Lee.Frost.Bargatze |
Parker Solar Probe, PSP, SWEAP Instrument Suite Description: Kasper, J.C., Abiad, R., Austin, G. et al., Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus, Space Scii. Rev., 204, 131–186 (2016)
Parker Solar Probe, PSP, SWEAP home page, Smithsonian Astrophysical Observatory
Parker Solar Probe, PSP, SWEAP Data Access web site, Smithsonian Astrophysical Observatory
Access to Data in CDF Format via ftp from SPDF
Access to Data in CDF Format via http from SPDF
Access to ASCII, CDF, and Plots via NASA/GSFC CDAWeb
Epoch Time Tags, TT2000, Nanoseconds since J2000 at Midpoint of the Integration
Solar Probe Cup, SPC, Data Quality Flag: an array of SPC data quality indicators
Solar Probe Cup, SCP, General Quality Flag: This flag documents all exceptional conditions that can affect normal data analysis of SPC observations. All flag values equal to zero signify good data with no exceptional conditions present.
Proton, p, Velocity, V estimate, from the first moment of the reduced distribution function, in the Spacecraft, Spacecraft frame, only good data qualities
Proton, p, Velocity, V estimate, upper uncertainty, from the first moment of the reduced distribution function, in the Spacecraft, Spacecraft frame, only good data qualities
Proton, p, Velocity, V estimate, lower uncertainty, from the first moment of the reduced distribution function, in the Spacecraft, Spacecraft frame, only good data qualities
Proton, p, Velocity, V estimate, from the first moment of the reduced distribution function, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Proton, p, Velocity, V estimate, upper uncertainty, from the first moment of the reduced distribution function, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Proton, p, Velocity, V estimate, lower uncertainty, from the first moment of the reduced distribution function, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Proton, p, Number Density, n estimate, from the zeroth moment of the reduced distribution function, only good data qualities
Proton, p, Number Density, n estimate, upper uncertainty, from the zeroth moment of the reduced distribution function, only good data qualities
Proton, p, Number Density, n estimate, lower uncertainty, from the zeroth moment of the reduced distribution function, only good data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, from the second moment of the reduced distribution function, only good data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, upper uncertainty, from the second moment of the reduced distribution function, only good data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, lower uncertainty, from the second moment of the reduced distribution function, only good data qualities
Primary Proton Population, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, only good data qualities
Primary Proton Population, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Primary Proton Population, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Primary Proton Population, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Primary Proton Population, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, only good data qualities
Proton, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Proton, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Proton, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, only good data qualities
Alpha Particle, He++, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Alpha Particle, He++, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Number Density, n estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Alpha Particle, He++, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Alpha Particle, He++, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, only good data qualities
Population 3, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, only good data qualities
Population 3, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Number Density, n estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Population 3, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, only good data qualities
Population 3, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3 Identifier, the third population fit, that is, in addition to primary Proton and Alpha peaks, only good data qualities
Spacecraft Position, Heliocentric Inertial, HCI, coordinates, cartesian
Spacecraft Velocity, Heliocentric Inertial, HCI, coordinates, cartesian
Spacecraft Position, Latitude, Carrington coordinates, spherical
Spacecraft Position, Longitude, Carrington coordinates, spherical
Proton, p, Velocity, V estimate, from the first moment of the reduced distribution function, in the Spacecraft, Spacecraft frame, all data qualities
Proton, p, Velocity, V estimate, upper uncertainty, from the first moment of the reduced distribution function, in the Spacecraft, Spacecraft frame, all data qualities
Proton, p, Velocity, V estimate, lower uncertainty, from the first moment of the reduced distribution function, in the Spacecraft, Spacecraft frame, all data qualities
Proton, p, Velocity, V estimate, from the first moment of the reduced distribution function, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Proton, p, Velocity, V estimate, upper uncertainty, from the first moment of the reduced distribution function, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Proton, p, Velocity, V estimate, lower uncertainty, from the first moment of the reduced distribution function, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Proton, p, Number Density, n estimate, from the zeroth moment of the reduced distribution function, all data qualities
Proton, p, Number Density, n estimate, upper uncertainty, from the zeroth moment of the reduced distribution function, all data qualities
Proton, p, Number Density, n estimate, lower uncertainty, from the zeroth moment of the reduced distribution function, all data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, from the second moment of the reduced distribution function, all data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, upper uncertainty, from the second moment of the reduced distribution function, all data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, lower uncertainty, from the second moment of the reduced distribution function, all data qualities
Primary Proton Population, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, all data qualities
Primary Proton Population, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Primary Proton Population, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Primary Proton Population, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, all data qualities
Proton, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Proton, p, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Proton, p, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, all data qualities
Alpha Particle, He++, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Alpha Particle, He++, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Alpha Particle, He++, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Spacecraft, Spacecraft frame, all data qualities
Population 3, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Velocity, V estimate, from 1-dimensional Maxwellian fitting, in the Radial-Tangential-Normal, Radial-Tangential-Normal frame, all data qualities
Population 3, Velocity, V estimate, one sigma error uncertainty, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, Number Density, n estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3, most probable Radial Thermal Speed, Vth estimate, from 1-dimensional Maxwellian fitting, all data qualities
Population 3 Identifier, the third population fit, that is, in addition to primary Proton and Alpha peaks, all data qualities
Data Quality Flag: The names of the data quality array fields.