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VG1 J/S/SS PLASMA WAVE SPECTROMETER RAW WAVEFORM 60MS V1.0 (PDS)

NSSDCA ID: PSFP-00544

Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1978-08-21 to 

Description

This description was generated automatically using input from the Planetary Data System.

Data Set Overview ================= This data set consists of electric field waveform samples from the Voyager 1 Plasma Wave Subsystem waveform receiver obtained during the entire mission. Data after 2007-05-31 will be added to the archive on subsequent volumes. The data set encompasses all waveform observations obtained in the cruise mission phases before, between, and after the Jupiter and Saturn encounter phases as well as those obtained during the two encounter phases. The Voyager 1 spacecraft travels from Earth to beyond 100 AU over the course of this data set. To provide some guidance on when some key events occurred during the mission, the following table is provided. Date Event 1977-09-05 Launch 1979-02-28 First inbound bow shock crossing at Jupiter 1979-03-22 Last outbound bow shock crossing at Jupiter 1980-11-11 First inbound bow shock crossing at Saturn 1980-11-16 Last outbound bow shock crossing at Saturn 1981-02-20 10 AU 1983-08-30 Onset of first major LF heliospheric radio event 1984-06-19 20 AU 1987-04-08 30 AU 1990-01-09 40 AU 1992-07-06 Onset of second major LF heliospheric radio event 1992-10-10 50 AU 1995-07-14 60 AU 1998-04-18 70 AU 2001-01-25 80 AU 2002-11-01 Onset of third major LF heliospheric radio event 2003-11-05 90 AU 2004-12-16 Termination shock crossing 2006-08-16 100 AU 2009-05-31 110 AU 2012-03-16 120 AU 2015-01-01 130 AU Data Sampling ============= The waveform is sampled at 4-bit resolution through a bandpass filter with a passband of 40 Hz to 12 kHz. 1600 samples are collected in 55.56 msec (at a rate of 28,800 samples per second) followed by a 4.44-msec gap. Each 60-msec interval constitutes a line of waveform samples. The data set includes frames of waveform samples consisting of up to 800 lines, or 48 seconds, each. The telemetry format for the waveform data is identical to that for images, hence the use of line and frame as constructs in describing the form of the data. Data Processing =============== Because there is no direct method for calibrating these data and because the raw format of packed, 4-bit samples is space-efficient, these data are not processed for archiving. The data may be plotted in raw form to show the actual waveform; this is useful for studying events such as dust impacts on the spacecraft. But the normal method of analyzing the waveform data is by Fourier transforming the samples from each line to arrive at an amplitude versus frequency spectrum. By stacking the spectra side-by-side in time order, a frequency-time spectrogram can be produced. Data ==== The waveforms are collections of samples of the electric field measured by the dipole electric antenna at a rate of 28,800 samples per second. The 4-bit samples provide sixteen digital values of the electric field with a linear amplitude scale, but the amplitude scale is arbitrary because of the automatic gain control used in the waveform receiver. The instantaneous dynamic range afforded by the 4 bit samples is about 23 dB, but the automatic gain control allows the dominant signal in the passband to be set at the optimum level to fit within the instantaneous dynamic range. With the gain control, the overall dynamic range of the waveform receiver is about 100 dB. The automatic gain control gain setting is not returned to the ground, hence, there is no absolute calibration for the data. However, by comparing the waveform spectrum derived by Fourier transforming the waveform to the spectrum provided by the spectrum analyzer data, an absolute calibration may be obtained in most cases. Ancillary Data ============== None Coordinates =========== The electric dipole antenna detects electric fields in a dipole pattern with peak sensitivity parallel to the spacecraft x-axis. However, no attempt has been made to correlate the measured field to any particular direction such as the local magnetic field or direction to a planet. This is because the spacecraft remains in a 3-axis stabilized orientation almost continuously, and these data are not obtained during the infrequent calibration turns. Furthermore, the automatic gain control feature would tend to counteract any orientation-dependent amplitude variations.

These data are available on-line from the Planetary Data System (PDS) at:

https://pds-ppi.igpp.ucla.edu/data/VG1-J-S-SS-PWS-1-EDR-WFRM-60MS-V1.0/

Alternate Names

  • VG1-J/S/SS-PWS-1-EDR-WFRM-60MS-V1.0

Discipline

  • Planetary Science: Fields and Particles

Additional Information

Spacecraft

Experiments

Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II

 

Personnel

NameRoleOriginal AffiliationE-mail
Prof. Donald A. GurnettData ProviderUniversity of Iowa
Dr. William S. KurthGeneral ContactUniversity of Iowawsk@space.physics.uiowa.edu
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