LESIA Observatoire de Paris-PSL CNRS vopdc cdpp Sorbonne Université cnes Université de Paris

Cassini/RPWS/HFR LESIA/Kronos N2 Data Collection V1.0

Thursday 7 January 2021, by Baptiste Cecconi

This collection is composed of Cassini/RPWS/NHFR (Radio and Plasma Waves Science / High Frequency Receiver) hourly N2 (Level 2) files.

This collection is part of the Cassini/RPWS/HFR LESIA/Kronos Collection(https://doi.org/10.25935/1SXH-AQ56).

Link to data repository

The files are available from the LESIA/Kronos data repository (link below). The repository file hierarchy and the link with the other LESIA/Kronos collection are described in Cecconi et al. (2021).


The data collection contains hourly Level 2 calibrated binary files, derived from the High Frequency Receiver (HFR) of Cassini/RPWS (Radio and Plasma Waves Science) dataset. This data collection has been calibrated for the receiver response. Measurements are provided in physical units (V2/Hz), but the antenna gain is not included.


The collection is composed of 143,889 binary files (389.34 GB) containing data as described in the table below.

N2 data record descriptions
ydh long 1 yyyydddhh of current file
num long 1 index of record in current file
t97 double 1 d time (decimal days, epoch = 1997.0)
f float 1 kHz frequency
dt float 1 ms effective integration time
df float 1 kHz effective bandwidth
autoX float 1 V2/Hz auto-correlation on the selected X antenna
autoZ float 1 V2/Hz auto-correlation on the Z antenna
crossR float 1 normalized cross-correlation (real part)
crossI float 1 normalized cross-correlation (imaginary part)
ant byte 1 Antenna selection mode (see below)

Antenna selection mode

The antenna selection mode is described by a numerical value, as follows:

  • 0: Ez only (Ex=Off)
  • 1: Ez and Ex=+X
  • 2: Ez and Ex=-X
  • 3: Ez and Ex=Dip
  • 11: Ez and Ex=+X (3-antenna mode)
  • 12: Ez and Ex=-X (3-antenna mode)

Modes 11 and 12 are used when 3-antenna mode is selected: a mode-11 record is always followed by a mode-12 record, with the same frequency setting.

NB: in some papers, the antenna naming conventions are different. The +X, -X, Z and Dip antenna are also known as u, v, w, D, respectively.

The total length of a single record is R = 45 bytes.

The file naming convention is: Pyyyyddd.hh

  • yyyy: Year in 4 digits
  • ddd: Day of year in 3 digits (0-padded)
  • hh: Hour of day in 2 digits (0-padded)

The file is composed of a raw series of N2 records (no header). Hence, the length of the file is equal to the number of records in file (N) multiplied by the length of a single record (R).

Coverage and sampling

  • Time range: 1998 to 2017
  • Time resolution: 30 seconds to 2 minutes.
  • Spectral range: 3.5 kHz to 16.1 MHz


The Cassini/RPWS/HFR LESIA/Kronos N2 (level 2) data collection has been produced by B. Cecconi, L. Lamy & P. Zarka, from the Observatoire de Paris/LESIA Cassini-RPWS team, with the support of CNRS and CNES.


Any question or request should be addressed to contact.maser@obspm.fr


  • Cecconi, B, P Zarka, L Lamy, D Vogl and G Boisnard. 2021 "CASSINI-RPWS-HFR LESIA/Kronos Database at Obs.Paris-PSL (Meudon)". V1.8. doi:10.25935/j7br-f293