PSP Solar Wind Electrons Alphas and Protons (SWEAP) SPC Ion Charge Flux Distributions, Electrical Current versus Time and Energy-per-Charge, Level 2 (L2), 0.2185 s Data

https://doi.org/10.48322/wpk2-yq48

2021-04-27 15:38:11Z

SPC Level 2 Ion Data

File Naming Format: psp_swp_spc_l2i_yyyymmdd_v01.cdf

Solar Probe Cup, SPC, charge flux distributions comprise electrical current as a function of time and energy-per-charge, with appropriate instrument response elements considered and calibrations applied. This data product contains measurements of ion flux as a function of energy organized into spectra. The SPC instrument measures one-dimensional distributions with a wide field of view. Please refer to the instrument paper for details.

This data set covers all periods for which the instrument was turned on and taking data in the solar wind in ion mode. This includes maneuvers affecting the spacecraft attitude and orientation.

The MODE_FLAG variable contains information about the type of spectrum being measured. "Ion Full Scan" spectra are marked with MODE_FLAG.DAT = 1. These spectra comprise a broad energy range typically with lower signal-to-noise than the more frequent "Ion Peak Tracking" spectra, which are marked with MODE_FLAG.DAT equal to zero. In the most frequent operating mode, ion full scans are executed about once every 30 s or whenever the peak signal from the solar wind is poorly defined.

SPC Encounter 1 Remarks

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.

SPC Cruise Phase Remarks

Measurements recorded during cruise phase are not all transmitted to Earth. The typical return is one spectrum out of every 32.

SPC Encounter 2 Remarks

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.

Parker Solar Probe SWEAP Rules of the Road

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.

• 1. Users should consult with the PI to discuss the appropriate use of instrument data or model results and to ensure that the users are accessing the most recently available versions of the data and of the analysis routines. Instrument team Science Operations Centers, SOCs, and/or Virtual Observatories, VOs, should facilitate this process serving as the contact point between PI and users in most cases.
• 2. Users should heed the caveats of investigators to the interpretations and limitations of data or model results. Investigators supplying data or models may insist that such caveats be published. Data and model version numbers should also be specified.
• 3. Browse products, Quicklook, and Planning data are not intended for science analysis or publication and should not be used for those purposes without consent of the PI.
• 4. Users should acknowledge the sources of data used in all publications, presentations, and reports: "We acknowledge the NASA Parker Solar Probe Mission and the SWEAP team led by J. Kasper for use of data.".
• 5. Users are encouraged to provide the PI a copy of each manuscript that uses the PI data prior to submission of that manuscript for consideration of publication. On publication, the citation should be transmitted to the PI and any other providers of data.

Please acknowledge the Principal Investigator J.C. Kasper for use of the Data. NASA open data policy applies. Consultation with the instrument team is strongly recommended.

spase://VSPO/NumericalData/ParkerSolarProbe/SWEAP/SPC/Level2/ChargeFluxDistributions/PT0.2185S

Online

Open

CDF

None

Please acknowledge the Principal Investigator J.C. Kasper. Please acknowledge the Data Providers and CDAWeb when using these Data.

Online

Open

CSV

Please acknowledge the Principal Investigator J.C. Kasper. Please acknowledge the Data Providers and CDAWeb when using these Data.

PT0.2185S

Epoch Time, TT2000, Midpoint of Integration

Epoch

Epoch Time Tags, TT2000, Nanoseconds since J2000 at Midpoint of the Integration

Warning: the Epoch time typically has an irregular cadence owing to frequent changes in the operating mode. TT2000 is measured in nanoseconds from J2000 with leap seconds included. Please refer to CDF TT2000 documentation with regards to this convention. This time corresponds to the first measurement of the spectrum. In accordance with SPDF standards, this epoch is interpreted a CDF_TT2000 time. It is acknowledged here that this epoch is not strictly equal to "terrestrial time" as it is defined in the CDF_TT2000 documentation nor is the calendar date interpreted by CDF_T2000 operation performed on this epoch strictly equal to Coordinated Universal Time, UTC This Parameter exhibits an increasing Monotonic Progression.

PT0.2185S

ns

1.0e-9>s

1990-01-01T00:00:00.000000000

2029-12-31T23:59:58.999000000

9999-12-31T23:59:59.999999999

Measurement Time

Time Series defined by using: EPOCH

measurement_time

Measurement Time: the time of flux measurement from the Epoch time at the beginning of spectrum

This variable gives the time that each specific flux measurement was made within the spectrum, counting up from the time that is specified in the Epoch variable

PT0.2185S

ns

1.0e-9>s

-1.0e+30

1.0e+30

-1.0e+31

Solar Probe Cup Modulator Voltage Index

mv_index

Solar Probe Cup, SPC, Modulator Voltage Index, mv_index

PT0.2185S

1

128

255

Solar Probe Cup Modulator Voltage, hi

Time Series defined by using: EPOCH

mv_hi

Solar Probe Cup, SPC, Modulator Voltage, hi, the upper bound of the oscillating potential barrier

Measurements of charge flux are made with respect to an AC discriminator voltage that oscillates between two values, which are stored in the variables denoted by using the parameter keys mv_lo and mv_hi.

PT0.2185S

V

-8000.0

8000.0

-1.0e+31

Solar Probe Cup Modulator Voltage, hi, measurement uncertainty

Time Series defined by using: EPOCH

mv_hi_DELTA_VAR

Solar Probe Cup, SPC, Modulator Voltage, hi, the upper bound of the oscillating potential barrier, measurement uncertainty

PT0.2185S

V

0.0

8000.0

-1.0e+31

Solar Probe Cup Modulator Voltage, lo

Time Series defined by using: EPOCH

mv_lo

Solar Probe Cup, SPC, Modulator Voltage, lo, the lower bound of the oscillating potential barrier

Measurements of charge flux are made with respect to an AC discriminator voltage that oscillates between two values, which are stored in the variables denoted by using the parameter keys mv_lo and mv_hi.

PT0.2185S

V

-8000.0

8000.0

-1.0e+31

Solar Probe Cup Modulator Voltage, lo, measurement uncertainty

Time Series defined by using: EPOCH

mv_lo_DELTA_VAR

Solar Probe Cup, SPC, Modulator Voltage, lo, the lower bound of the oscillating potential barrier, measurement uncertainty

PT0.2185S

V

0.0

8000.0

-1.0e+31

Solar Probe Cup Sensor Plate A Current

Time Series defined by using: EPOCH

a_current

Solar Probe Cup, SPC, Sensor Plate A Current

PT0.2185S

pA

1.0e-12>A

-1.0e+06

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate B Current

Time Series defined by using: EPOCH

b_current

Solar Probe Cup, SPC, Sensor Plate B Current

PT0.2185S

pA

1.0e-12>A

-1.0e+06

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate C Current

Time Series defined by using: EPOCH

c_current

Solar Probe Cup, SPC, Sensor Plate C Current

PT0.2185S

pA

1.0e-12>A

-1.0e+06

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate D Current

Time Series defined by using: EPOCH

d_current

Solar Probe Cup, SPC, Sensor Plate D Current

PT0.2185S

pA

1.0e-12>A

-1.0e+06

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate A Current, measurement uncertainty

Time Series defined by using: EPOCH

a_current_DELTA_VAR

Solar Probe Cup, SPC, Sensor Plate A Current, measurement uncertainty

Sources of uncertainty include the measurement digitization error, the voltage pair and waveform error, non-stationarity of conditions during the measurement period, and the propagated uncertainty in absolute calibration.

PT0.2185S

pA

1.0e-12>A

0.0

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate B Current, measurement uncertainty

Time Series defined by using: EPOCH

b_current_DELTA_VAR

Solar Probe Cup, SPC, Sensor Plate B Current, measurement uncertainty

Sources of uncertainty include the measurement digitization error, the voltage pair and waveform error, non-stationarity of conditions during the measurement period, and the propagated uncertainty in absolute calibration.

PT0.2185S

pA

1.0e-12>A

0.0

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate C Current, measurement uncertainty

Time Series defined by using: EPOCH

c_current_DELTA_VAR

Solar Probe Cup, SPC, Sensor Plate C Current, measurement uncertainty

Sources of uncertainty include the measurement digitization error, the voltage pair and waveform error, non-stationarity of conditions during the measurement period, and the propagated uncertainty in absolute calibration.

PT0.2185S

pA

1.0e-12>A

0.0

1.0e+06

-1.0e+31

Solar Probe Cup Sensor Plate D Current, measurement uncertainty

Time Series defined by using: EPOCH

d_current_DELTA_VAR

Solar Probe Cup, SPC, Sensor Plate D Current, measurement uncertainty

Sources of uncertainty include the measurement digitization error, the voltage pair and waveform error, non-stationarity of conditions during the measurement period, and the propagated uncertainty in absolute calibration.

PT0.2185S

pA

1.0e-12>A

0.0

1.0e+06

-1.0e+31

Solar Probe Cup Bulk Flow Angles: Azimuth and Elevation

Time Series defined by using: EPOCH

flow_angle

Solar Probe Cup, SCP, Bulk Flow Angles: Azimuth and Elevation: the angles associated with the mean flow into the cup, SPC coordinates

This flow component is across the sensor with respect to the SPC sensor coordinate system rudimentary estimate of the bulk flow angle into the sensor. This variable has dimension ⨯ N_t, where the first element is the azimuthal angle and the second element is the elevation angle. This flow angle is estimated by using the linear cold-plasma approximation and considerin three-point neighborhood in time at the peak flux measurement. It does not account for spreading of the beam in the instrument, which may be significant. Please refer to Case et al. 2019 and/or consult the instrument team regarding systematics in accuracy and precision for this quantity. Positive azimuthal angles correspond to deflections towards sensor plate and C. Negative azimuthal angles correspond to deflections towards sensor plate and D. In encounter configuration, positive azimuth angles correspond to -T flow directions in the RTN reference frame. Positive elevation angles correspond to deflections towards sensor plate and B. Negative elevation angles correspond to deflections towards sensor plate and D. In encounter configuration, positive elevation angles correspond to -N flow directions in the RTN reference frame.

PT0.2185S

rad

-1.5708

1.5708

-1.0e+31

Solar Probe Cup Bulk Flow Azimuth and Elevation Angles, uncertainties

Time Series defined by using: EPOCH

flow_angle_DELTA_VAR

Solar Probe Cup, SPC, Bulk Flow Azimuth and Elevation Angles, uncertainties in the angle of flow into the cup in SPC coordinates

Sources of uncertainty can include propagated calibration uncertainty, propagated current measurement uncertainty, non-stationarity of the flow angle over the period of measurement, and confusion between multiple ion species

PT0.2185S

rad

0.0

1.5708

-1.0e+31

Solar Probe Cup Charged Flux Density

Time Series defined by using: EPOCH

diff_charge_flux_density

Solar Probe Cup, SPC, Charged Flux Density: This variable is a measure of the charge flux density of the solar wind measured over the energy range defined by the modulator voltage pair. The calibrated effective area of the SPC instrument has been taken into account. This measured charge flux density is equivalent to the total charge crossing a surface oriented perpendular to Z-axis in the Spacecraft, SC, reference frame per unit area per unit time due to charge carriers having energy-per-charge in the range between the modulator voltage low and high, MV_LO and MV_HI, settings. This quantity is estimated by using the linear, cold plasma approximation for the mean flow angle of the solar wind into the sensor. It does not account for spreading of the beam in the instrument, which may be significant. Please refer to Case et al. 2019 and/or consult the instrument team regarding systematics in accuracy and precision for this quantity. Appendix 3.1 provides a walk through for estimating the reduced distribution function from this variable.

This is the differential charge flux density of the solar wind measured over the energy range defined by the modulator voltage pair. The calibrated effective area of the cup has been taken into account.

PT0.2185S

pA/cm^-2

1.0e-8>A/m^2

-1.0e+30

1.0e+30

-1.0e+31

Solar Probe Cup Differential Charged Flux Density, uncertainty

Time Series defined by using: EPOCH

diff_charge_flux_density_DELTA_VAR

Solar Probe Cup, SPC, Differential Charged Flux Density, uncertainty

Sources of uncertainty include all propagated uncertainties plus the uncertainty associated with the effective area of the sensor at the estimated flow angle.

PT0.2185S

pA/cm^-2

1.0e-8>A/m^2

0.0

1.0e+06

-1.0e+31

Solar Probe Cup Operating Mode Flag

Time Series defined by using: EPOCH

MODE_FLAG

Solar Probe Cup, SPC, Operating Mode Flag: signifies the SPC operating mode at the time of measurement.

The Mode Flag contains information about the type of spectrum being measured. "Ion full scan" spectra are marked with MODE_FLAG.DAT equal to 1. The Ion full scan spectra compris broad energy range, typically with lower signal-to-noise than the more frequent "Ion peak tracking" spectra, which are marked with MODE_FLAG.DAT equal to 0. In the most frequent operating mode, Ion full scans are executed about once every 3 or whenever the peak signal from the solar wind is poorly defined. Mode Flag Values: 0=Ion Peak Tracking Mode, 1=Ion Full Scan Mode, 2=Ion Flux-Angle Mode, 3=Ion Calibration Mode, 4=Electron Peak Tracking Mode, 5=Electron Full Scan Mode, 6=Electron Flux-Angle Mode, 7=Electron Calibration Mode.

PT0.2185S

0

254

255