The data product solo_L3_rpw-hfr-surv-flux provides fully calibrated E-field spectra, measured in survey normal and burst modes over the HFR receiver frequency range of the Solar Orbiter/RPW instrument.

DOI: https://doi.org/10.57780/ESA-3XCJD4W
Publisher: ESA
Citation: European Space Agency & Maksimovic, M. (2024). RPW, Radio and Plasma Waves instrument (Version v1.0) [Dataset]. European Space Agency. https://doi.org/10.57780/ESA-3XCJD4W

Link to the data repository

Data files are available from the Solar Orbiter Archive home page.

Copies of the files are also stored in the LIRA local data repository.

Data product overview

The radio flux density is given in physical units (W/m^2/Hz or SFU).
The calibration takes already account of the harness + pre-amplifiers + antennas gain contributions. The receiver background has been already removed from the signal. The antenna calibration method is presented in this paper.

Data product key facts
Type of data Spectrum
Intensity units W/m^2/Hz or SFU or dB
Max Frequency range 375 to 16375 kHZ
Max Frequency number 50
Min Frequency step 50 kHz
Frequency scale Linear
Time resolution 0.1 sec to 5.4 seconds
Data format CDF
File name solo_L3_rpw-hfr-surv-flux_[YYYYMMDD]_V[version].cdf
Granularity 1 file per day
Expected data volume 17 MBytes per file

Data organization

Each CDF record contains data for a given HFR frequency spectrum (also called sweep hereafter). Each sweep covers the 50 cleanest frequencies over the 321 available.
Epoch times correspond to the acquisition time of the first data sample in the current HFR sweep. The acquisition times for next data samples in the sweep can be computed using the offset values (in seconds) in the ELAPSED_TIME_SINCE_EPOCH zVariable. Missing/bad data samples are interpolated.

Table below gives the name, data type, units and description of the main zVariables stored in the CDF file.
In the the “TYPE” column, the expected size (i.e., number of elements along each dimension) of the zVariable for a CDF record is given between bracket (e.g., “[1]”).
Non-record-variant zVariables are indicated by a “(NRV)” additional label in the “TYPE” column.

NAMETYPEUNITDESCRIPTION
Epoch CDF_TIME_TT2000 [1] ns Epoch time of the record
Taken at the acquisition time of the first data sample in the current HFR sweep
FREQUENCY CDF_FLOAT[50] (NRV) Hz HFR frequency values
SENSOR_CONFIG CDF_UINT1[1] unitless Channel receiver antenna configuration. Possible values are: 9 = (V1-V2), 10 = (V2-V3), 11 = (V3-V1)
ELAPSED_TIME_SINCE_EPOCH CDF_FLOAT[50] s Elapsed time in seconds since the beginning of the current sweep
INTERPOL_FLAG CDF_UINT1[50] unitless Flag that indicates the state of the current record. Possible values are: 0 = no data sample, 1 = real data sample, 2 = interpolated data sample, 3 = data sample amplitude is below background
PSD_V2 CDF_FLOAT[50] V^2/Hz Power spectral density measured by the HFR receiver (preamplifier contribution is included)
PSD_FLUX CDF_FLOAT[50] W/m2/Hz Radio flux density in physical units measured at the spacecraft location, after receiver background subtraction and antenna calibration
PSD_SFU CDF_FLOAT[50] sfu Radio flux density in Solar flux units (i.e., 10^22 W/(m^2 Hz)) normalized to 1 AU, after receiver background substraction and antenna calibration
PSD_SFU_DB CDF_FLOAT[50] unitless Normalized Radio flux density in dB measured at the spacecraft location. Values are computed using the relation 10*alog10(PSD_FLUX / BG), where BG is an estimation of the background computed from the 1% percentile of the signal for each frequency. SC_POS_HCI CDF_FLOAT[3] km Spacecraft position in the Heliocentric Inertial (HCI) system

Rules of use

Please read the text of the Rules_of_use global attribute in the CDF files.
See also in https://rpw-datacenter.obspm.fr/spip.php?article4.


Caveats and known issues

Table below gives the list of main known issues and the actions taken to mitigate them.
Please read the CAVEATS global attribute entries in the CDF files to be aware of the possible issues and limitations concerning data.

ISSUEMITIGATION(S)
Some RPW HFR frequency channels are affected by Electromagnetic contaminations. HFR E-field spectra are interpolated over the 50 cleanest frequency channels
RPW MY (3) electrical antenna signal was lost intermittently between November 13th and March 15th. HFR acquisitions were impacted when measurements were performed on the dipoles V3-V1 and V2-V1. Specific entry added for the global attribute CAVEATS and QUALITY_FLAG zVariable set to 1 for impacted records.

Release notes

See MODS global attribute in the CDF files for an history of the data modifications.


Authors

Antonio Vecchio, Xavier Bonnin, Quynh Nhu Nguyen and Milan Maksimovic, with the support of Vratislav Krupar


References

• The Solar Orbiter Radio and Plasma Waves (RPW) instrument, Maksimovic et al., A&A, 2020 (https://doi.org/10.1051/0004-6361/201936214)
• Solar Orbiter/RPW antenna calibration in the radio domain and its application to type III burst observations, Vecchio et al., A&A, 2021 (https://doi.org/10.1051/0004-6361/202140988)
• THR-Calibration Procedures, A. Vecchio, [ROC-TST-CAL-PRC-00031-LES 1.0] (available on demand)
Metadata Definition for Solar Orbiter Science Data, Helen R. Middleton
RPW Data Product Description Document (DPDD)
NASA CDF Web portal


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