Release notes for PSP/FIELDS data release 12

Data Release 12

PSP/FIELDS Data Release 12 includes survey and select data from Encounter 11 (perihelion February 25, 2022). Data was made publicly available on August 1, 2022.

The release notes below detail anomalies in the FIELDS data from Encounter 11, and new data products which are now publicly available (for the entire PSP mission, up to and including Encounter 11).

Data Anomalies

RFS/LFR Data Gap

During Encounter 11, a commanding error resulted in a gap in RFS/LFR data near perihelion, as shown in the figure below. There is no LFR data (and, therefore, no possibility of QTN data with electron density/temperature) during this gap, which lasted for approximately 4 days surrounding perihelion. RFS/HFR data was unaffected, except during short intervals near times of bias sweeps.

Gap in RFS/LFR data near perihelion 11

The underlying commanding issue was identified and resolved, and RFS LFR data was successfully recorded during Encounter 12.

Anomalous Bias

The whip bias currents on the V1-V4 FIELDS antennas are typically set to matching negative values. For two intervals during Encounter 11, the V3 bias current was set to a positive value which did not match the current on the other three antennas. The cause for this out-of-family bias current is still under investigation. A new data quality flag ANOM_BIAS has been created and is used to mark the time intervals when anomalous bias conditions are present.

Anomalous bias interval during Encounter 11. The third panel shows the V3 bias current. Times of anomalous bias conditions are indicated in the bottom panel, which shows the data quality flag variable.

New Data Products

Level 2 AEB data

Level 2 Antenna Electronics Board (AEB) data is now available. The FIELDS Main Electronics Package contains two Antenna Electronics Boards (AEB1 and AEB2), which are nearly functionally identical. AEB1 processes signals from the FIELDS V1, V2, and V5 sensors, while AEB2 processes V3 and V4. For details on AEB1 and AEB2, see the FIELDS instrument paper.

The Level 2 AEB files contain housekeeping data from both AEBs, including bias voltages and currents for each of the V1-V5 sensors, along with temperature information from the FIELDS preamplifiers and MEP. The plot below shows Level 2 AEB data from PSP Encounter 11. The plot panels show the temperature of the V1 preamplifier psp_fld_l2_aeb1_PA1_TEMP and the bias current applied to the V1 whip psp_fld_l2_aeb1_V1_WHIP_CURR. The preamp temperature increases near perihelion, as does the magnitude of the (negative) bias current applied to the whip.

Example of Level 2 AEB data
Level 2 AEB data

During normal operations, AEB housekeeping data are returned in telemetry packets. Packets are generated for each update to AEB settings, and periodically for monitoring purposes. During bias sweeps, settings are updated too rapidly for each change to be telemetered in an individual packet, so the bias settings during the sweep are inferred based on FIELDS instrument command history. Telemetry flag variables psp_fld_l2_aeb1_TELEM_FLAG and psp_fld_l2_aeb2_TELEM_FLAG indicate the source of the data in the Level 2 AEB CDF files.

An example of Level 2 AEB data during a bias sweep is shown below. The top panel in the plot shows DFB DC waveform data from the V1 antenna, and the bottom panel shows the commanded (DAC) values of the bias current applied to the V1 whip.

AEB current and DFB voltage during a bias sweep
AEB current and DFB voltage during a bias sweep during Encounter 11

Level 3 QTN data from GSFC

A new Level 3 data product, rfs_lfr_qtn is available at the FIELDS SOC site. Like the Level 3 sqtn_rfs_V1V2 data, this data set is based on analysis of RFS/LFR data. The rfs_lfr_qtn data contains electron density and plasma frequency variables, along with error estimates. The files are produced at GSFC by Vratislav Krupar, and are available in yearly files in the directory:

An example plot of data from Encounter 10 is shown below. Details of the data variables and processing algorithms are available in the CDF file metadata.

rfs_lfr_qtn data during Encounter 10