HPDE.io

ISEE 1 Plasma wave experiment (PWE) Spectrum Analyzer

ResourceID
spase://NASA/NumericalData/ISEE1/PWE/SA/PT1S

Description

'The ISEE-1 and -2 Plasma Wave Investigation' D. A. Gurnett, F. L. Scarf, R. W. Fredricks, and E. J. Smith, IEEE Transactions on Geoscience Electronics, Vol. GE-16, p. 225-230, 1978. The International Sun-Earth Explorer (ISEE) Program consisted of three satellites intended to study the Earth's magnetosphere and the solar wind. ISEE-1 and ISEE-2 were launched on October 22, 1977 into highly elliptical geocentric orbits. The satellites passed through the magnetosphere and into the magnetosheath during each orbit. ISEE-3 was launched on August 12, 1978 and subsequently inserted into a 'halo orbit' about the the libration point situated about 240 earth radii (Re) upstream between the earth and the sun. Plasma passing this point arrives at the Earth about one hour later where it may cause changes that can be observed by ISEE 1 and ISEE-2. These two spacecraft, separated by a variable distance and with similar instrument complements, were intended to resolve the space-time ambiguity associated with measurements by a single spacecraft on thin boundaries which may be in motion such as the bow shock and the magnetopause. ISEE-1 and ISEE-3 were the principal U. S. contributions to the International Magnetospheric Study. ISEE-2 was built and managed by the European Space Agency. In September 1982 ISEE-3 was diverted from its 'halo orbit' to explore the earth's deep tail region through much of 1983 on its way to an encounter with the comet Giacobini Zinner in September 1985. ISEE-1 had a complement of thirteen experiments to measure the waves, fields, plasma, and particles. The University of Iowa Plasma Wave Instrument (PWI) was one of these thirteen. The ISEE-1 plasma waves instrument provided a comprehensive determination of wave characteristics over a broad frequency range, including high-frequency resolution spectrum scans, simultaneous high-time resolution electric and magnetic frequency spectrum measurements, wave normal and Poynting flux measurements, and wide-band waveform measurements. PWI sampled the environment using three electric dipole antennas with lengths of 215, 73.5, and 0.61 meters for electric-field measurements, and a triaxial search coil antenna with three 16-in high permeability mu-metal cores each wound with 10,000 turns of wire and a preamplifier for magnetic-field measurements. The experiment's main electronics consisted of four main elements: 1) a narrow-band sweep frequency receiver, 2) a pair of high time resolution spectrum analyzers, 3) a wave normal analyzer, and 4) an analog waveform receiver (also called a wide-band receiver). These elements could be electrically connected to the six antennas in various combinations in flight. Data for this file originate with the spectrum analyzers. The PWI Spectrum Analyzers were designed to provide high time resolution spectrum measurements for resolving wave emissions that are bursty or of a nonlinear nature. The pair consisted of a 20-channel analyzer covering the range from 5.62 Hz to 311 kHz, and a 14-channel analyzer covering the range from 5.62 Hz to 10 kHz. These analyzers have a relatively coarse frequency resolution, with four frequency channels per decade and bandwidths of +/-15 percent up to 10 kHz and +/-7.5 percent for 10 kHz and above. The center frequencies and bandwidths of the 20- and 14-channel analyzers are identical. The 20-channel analyzer was nominally intended for electric field measurements (which extend up to higher frequencies than the magnetic measurements), and the 14-channel analyzer was nominally intended for magnetic field measurements. All channels are sampled simultaneously so that electric-to-magnetic field ratios could be accurately determined. For a detailed description of the Plasma Wave Instrument, the reader is referred to the IEEE Geoscience Electronics reference above. A common acronym for the plasma waves instrument in older documentation is GUM, which stands for for Gurnett Mother. Since this acronym is not easily recognizable by the space physics community and since no official acronym is provided in the instrument paper, the more common short hand 'PWI' is used to refer to the Plasma Wave Instrument in this archive.

View XML | View JSON | Edit

Details

Version:2.2.9

NumericalData

ResourceID
spase://NASA/NumericalData/ISEE1/PWE/SA/PT1S
ResourceHeader
ResourceName
ISEE 1 Plasma wave experiment (PWE) Spectrum Analyzer
AlternateName
ISEE-A Gurnett PWI SA
ReleaseDate
2020-07-07 21:14:40Z
Description

'The ISEE-1 and -2 Plasma Wave Investigation' D. A. Gurnett, F. L. Scarf, R. W. Fredricks, and E. J. Smith, IEEE Transactions on Geoscience Electronics, Vol. GE-16, p. 225-230, 1978. The International Sun-Earth Explorer (ISEE) Program consisted of three satellites intended to study the Earth's magnetosphere and the solar wind. ISEE-1 and ISEE-2 were launched on October 22, 1977 into highly elliptical geocentric orbits. The satellites passed through the magnetosphere and into the magnetosheath during each orbit. ISEE-3 was launched on August 12, 1978 and subsequently inserted into a 'halo orbit' about the the libration point situated about 240 earth radii (Re) upstream between the earth and the sun. Plasma passing this point arrives at the Earth about one hour later where it may cause changes that can be observed by ISEE 1 and ISEE-2. These two spacecraft, separated by a variable distance and with similar instrument complements, were intended to resolve the space-time ambiguity associated with measurements by a single spacecraft on thin boundaries which may be in motion such as the bow shock and the magnetopause. ISEE-1 and ISEE-3 were the principal U. S. contributions to the International Magnetospheric Study. ISEE-2 was built and managed by the European Space Agency. In September 1982 ISEE-3 was diverted from its 'halo orbit' to explore the earth's deep tail region through much of 1983 on its way to an encounter with the comet Giacobini Zinner in September 1985. ISEE-1 had a complement of thirteen experiments to measure the waves, fields, plasma, and particles. The University of Iowa Plasma Wave Instrument (PWI) was one of these thirteen. The ISEE-1 plasma waves instrument provided a comprehensive determination of wave characteristics over a broad frequency range, including high-frequency resolution spectrum scans, simultaneous high-time resolution electric and magnetic frequency spectrum measurements, wave normal and Poynting flux measurements, and wide-band waveform measurements. PWI sampled the environment using three electric dipole antennas with lengths of 215, 73.5, and 0.61 meters for electric-field measurements, and a triaxial search coil antenna with three 16-in high permeability mu-metal cores each wound with 10,000 turns of wire and a preamplifier for magnetic-field measurements. The experiment's main electronics consisted of four main elements: 1) a narrow-band sweep frequency receiver, 2) a pair of high time resolution spectrum analyzers, 3) a wave normal analyzer, and 4) an analog waveform receiver (also called a wide-band receiver). These elements could be electrically connected to the six antennas in various combinations in flight. Data for this file originate with the spectrum analyzers. The PWI Spectrum Analyzers were designed to provide high time resolution spectrum measurements for resolving wave emissions that are bursty or of a nonlinear nature. The pair consisted of a 20-channel analyzer covering the range from 5.62 Hz to 311 kHz, and a 14-channel analyzer covering the range from 5.62 Hz to 10 kHz. These analyzers have a relatively coarse frequency resolution, with four frequency channels per decade and bandwidths of +/-15 percent up to 10 kHz and +/-7.5 percent for 10 kHz and above. The center frequencies and bandwidths of the 20- and 14-channel analyzers are identical. The 20-channel analyzer was nominally intended for electric field measurements (which extend up to higher frequencies than the magnetic measurements), and the 14-channel analyzer was nominally intended for magnetic field measurements. All channels are sampled simultaneously so that electric-to-magnetic field ratios could be accurately determined. For a detailed description of the Plasma Wave Instrument, the reader is referred to the IEEE Geoscience Electronics reference above. A common acronym for the plasma waves instrument in older documentation is GUM, which stands for for Gurnett Mother. Since this acronym is not easily recognizable by the space physics community and since no official acronym is provided in the instrument paper, the more common short hand 'PWI' is used to refer to the Plasma Wave Instrument in this archive.

Acknowledgement
Users of the ISEE-1 PWI SA data are encouraged to acknowledge NASA CDAWeb and The University of Iowa as the source of the data in any publication. ISEE-1 PWI SA data are open to everyone. However, users of these data are encouraged to contact the PI institute and the U of I ISEE website should questions arise.
Contacts
RolePerson
1.PrincipalInvestigatorspase://SMWG/Person/Donald.A.Gurnett
2.MetadataContactspase://SMWG/Person/Jolene.S.Pickett
3.MetadataContactspase://SMWG/Person/Larry.J.Granroth
4.MetadataContactspase://SMWG/Person/Chris.W.Piker
InformationURL
Name
The University of Iowa ISEE-1 PWI Page
URL
http://www-pw.physics.uiowa.edu/isee/
Description
Language
en
PriorIDs
spase://VWO/NumericalData/ISEE1/PWE/SA.PT1S
spase://VSPO/NumericalData/ISEE1/PWE/SA/PT1S
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
Availability
Online
AccessRights
Open
AccessURL
Name
FTPS from SPDF (not with most browsers)
URL
ftps://spdf.gsfc.nasa.gov/pub/data/isee/isee1/
Description

Direct link to CDF format data via FTP from the SPDF.

AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/isee/isee1/
Description

Access to Data in CDF Format via http from SPDF

AccessURL
Name
CDAWeb
URL
https://cdaweb.sci.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=ISEE1_PWI_SA&index=sp_phys
ProductKey
ISEE1_PWI_SA
Description

Access to ASCII, CDF, and plots via NASA/GSFC CDAWeb

Format
CDF
Encoding
None
Acknowledgement
Users of the ISEE-1 PWI SA data are encouraged to acknowledge NASA CDAWeb and The University of Iowa as the source of the data in any publication.
AccessInformation
RepositoryID
spase://SMWG/Repository/UIowa/RadioPlasmaWaveGroup
Availability
Online
AccessRights
Open
AccessURL
Name
HTTP access to files at The University of Iowa
URL
http://www-pw.physics.uiowa.edu/plasma-wave/isee/data/ISEE1/cdf/
Description

Direct link to CDF format data via HTTP from the University of Iowa.

Format
CDF
Encoding
None
Acknowledgement
Users of the ISEE-1 PWI SA data are encouraged to acknowledge NASA CDAWeb and The University of Iowa as the source of the data in any publication.
ProcessingLevel
Calibrated
InstrumentIDs
spase://SMWG/Instrument/ISEE1/PWE
MeasurementType
Waves.Passive
MeasurementType
Spectrum
TemporalDescription
TimeSpan
StartDate
1977-10-22 19:13:20
StopDate
1987-09-26 06:07:59
Note
Cadence
PT1S
Caveats
Quality Note: This experiment showed no anomalies in its operation throughout the lifetime of the spacecraft. Interference from four sources were occasionally observed and flags to identify the possible presence of these sources are included in the 'E_Quality' and 'B_Quality' variables. The data from the search coil magnetometers have possible interference when the internal Z-measurement calibration operates and when the Energetic Electrons Instrument's scan platform (D. J. Williams) passes through certain positions. The data from the electric field sensors have possible interference when the Plasma Density Instrument (C. C. Harvey) applies signals to the antennas and when the Quasi-static Electric Fields Instrument (F. S. Mozer) performs bias sweeps. The Energetic Electrons Instrument's scan platform generates noise which shows up as bursts in the search coil data in the frequency range from 56.2 Hz to 562 Hz when the scan platform passes through the spin plane. When the scan platform is operating, the interference occurs approximately every six spins. When the SCAN flag is set in the 'B_Quality' variable, one needs to examine the data to determine whether or not the glitches exceed the naturally occurring signals in this frequency range. The Z-MEAS flag indicates when internally generated signals are applied to the search coil antennas. When the Z-MEAS flag is set in the 'B_Quality' variable, one needs to examine the data to determine whether or not the glitches exceed the naturally occurring signals in the search coil data. The MOZER flag identifies possible interference when the Quasi-static Electric Field's Instrument performs a bias sweep. In normal operations a bias sweep was performed in a two second period every 128 seconds. This resulted in spikes appearing in the electric field data. When the MOZER flag is set in the 'E_Quality' variable, one needs to examine the data to determine whether or not the interference exceeds the naturally occurring signals in the electric field data. The HARVEY flag identifies possible interference when the Plasma Density Instrument injects signals on either of the long electric dipole antennas. When the HARVEY flag is set in the 'E_Quality' variable, one needs to examine the data to determine whether or not the interference exceeds the naturally occurring signals in the electric field data. When the Plasma Density Instrument interference occurs, it frequently cycles on and off at periods of 128, 256, or 512 seconds. Interference noise generated by the solar array is frequently evident in the electric field data at low frequencies up to about 100 Hz. This particular source is NOT identified in the 'E_Quality' variable, thus data from lowest 6 frequency bins of the 'Ev_Spectra' and 'Eu_Spectra' variables are always suspect. Nominally the 20-channel spectrum analyzer was connected to one of the electric antennas and the 14-channel spectrum analyzer was connected to one of the magnetic search coils, but about 2.2 percent of the SA data were collected with the analyzers swapped. This arrangement was required because the SFR and the 20-channel analyzer were fed off the same antenna selection switch. So in order to send magnetic field signals to the Sweep Frequency Receiver (SFR) for high frequency resolution measurements, the 20-channel analyzer had to be connected to a magnetic antenna. In this state, the upper 6 channels of magnetic field data are collected above the search search coil's cutoff frequency. Archive users should be aware that low magnetic spectral density values above 10 kHz are not physically meaningful. For any type of survey study, it would be best to reject the respective data when an interference flag is set, and to reject all magnetic spectral densities above 10 kHz. For high-time resolution event studies, it would be appropriate to examine the data in detail to see whether or not the naturally occurring or the interference signals dominate.
Parameter #1
Name
Center Frequencies
ParameterKey
Frequencies
Description

Channel Frequency Centers, 20 (5.62 Hz to 311,000 Hz). These are the frequency channels for all 20 of the spectrum analyzer bands. In instances where data are collected via the 14-channel analyzer, the upper 6 wave power measurements will contain fill values.

Units
Hz
Support
SupportQuantity
Other
Parameter #2
Name
Epoch
ParameterKey
Epoch
Description

Spacecraft Event Time in UTC for the start of an SA measurement.

Units
ms
Support
SupportQuantity
Temporal
Parameter #3
Name
SA Ev Spectra
ParameterKey
Ev_Spectra
Description

Spin Plane E-Field Spectra, 215 meter long-wire antenna. These data are collected primarily via the fine wire electric dipole antenna which had a tip to tip length of 215 meters. The Ev antenna was used to collect over 99% of the E-field measurements obtained by the PWI. Most of the time (98.3%) these data were collected via the ESA (Electric Spectrum Analyzer). Though a small fraction of the data are from the MSA (Magnetic Spectrum Analyzer). The two analyzers have almost identical channel centers and bandwidths, except that ESA has 6 more bands above the highest band of the MSA. When the MSA is used to read an electric antenna, the upper 6 bands are marked with fill data. This antenna was shared with the Heppner DC electric-field experiment. The 'E_Quality' variable flags times when known spacecraft noise sources are present in the E-field data.

Units
V^2 m^-2 Hz^-1
Wave
WaveType
PlasmaWaves
WaveQuantity
ACElectricField
FrequencyRange
SpectralRange
RadioFrequency
Low
5.62
High
311000
Units
Hz
Parameter #4
Name
SA Eu Spectra
ParameterKey
Eu_Spectra
Description

Spin Plane E-Field Spectra, 73.5 meter two-sphere antenna. Less that 0.5% of electric spectra in this data set were collected via the Eu antenna. This variable is almost always empty. The Eu sensor is a two-sphere electric antenna which had a sphere-to-sphere separation of 73.5 meters. The spheres on the u-axis have a diameter of 8.0 cm and each contains a high-impedance preamplifier which provides signals to the main electronics box which contained the spectrum analyzers. This antenna was shared with the Mozer quasi-static electric-field instrument. Consult the 'E_Quality' variable for issues regarding Ev_Spectra values.

Units
V^2 m^-2 Hz^-1
Wave
WaveType
PlasmaWaves
WaveQuantity
ACElectricField
FrequencyRange
SpectralRange
RadioFrequency
Low
5.62
High
311000
Units
Hz
Parameter #5
Name
Electric Data Quality Flags
ParameterKey
E_Quality
Description

Integer combining all E-antenna data quality flags, 0 = no issues detected. A bitwise OR'ing of all known issue values for this record. The following issue values are defined. (0x4: MOZER) if this flag is present then the Quasi-static Electric Fields instrument (F. S. Mozer) is performing a bias sweep, (0x8: HARVEY) identifies possible interference that occurs when the Plasma Density instrument (C. C. Harvey) injects signals on either of the long electric dipole antennas.

Support
SupportQuantity
Other
Parameter #6
Name
SA Bz Spectra
ParameterKey
Bz_Spectra
Description

Spin Axis B-Field Spectra, Bz search coil. These data are collected via the z-axis Magnetic Search Coil (Bz) which has an upper cutoff frequency of 10 kHz. It's constructed of a 16 inch mu-metal core and wound with 10000 turns wire. Almost 99% of all magnetic field measurements from the PWI were collected via the Bz search coil. NOTE: When they are present at all, the upper 6 frequency indices contain data collected above the search coil's upper cutoff frequency. Though these data are included for completeness, all samples above 10 kHz are not calibrated data and should be used with caution. See the 'B_Quality' variable and the 'Quality_note' for issues regarding Bz_Spectra

Units
nT^2 Hz^-1
Wave
WaveType
PlasmaWaves
WaveQuantity
ACMagneticField
FrequencyRange
SpectralRange
RadioFrequency
Low
5.62
High
311000
Units
Hz
Parameter #7
Name
SA Bv Spectra
ParameterKey
Bv_Spectra
Description

Spin Plane B-Field Spectra, Bv search coil. These data were collected via the V-axis Magnetic Search Coil (Bv). This coil had the same physical properties as the Bz coil but was mounted perpendicular to the Bz coil. The Bv coil axis pointed along the V direction, which is within the spacecraft spin plane. This variable is usually empty. Less than 2.5% of magnetic spectra were collected via this search coil. See the 'B_Quality' variable and the 'Quality_note' for issues regarding Bv_Spectra.

Units
nT^2 Hz^-1
Wave
WaveType
PlasmaWaves
WaveQuantity
ACMagneticField
FrequencyRange
SpectralRange
RadioFrequency
Low
5.62
High
311000
Units
Hz
Parameter #8
Name
SA Bu Spectra
ParameterKey
Bu_Spectra
Description

Spin Plane B-Field Spectra, Bu search coil. These data were collected via the U-axis Magnetic Search Coil (Bu). This coil had the same physical properties as the Bv coil but was mounted perpendicular to both the Bz and Bv coils. The Bu coil axis pointed along the U direction, which is also within the spacecraft spin plane. This variable is almost always empty. Less than 0.1% of magnetic spectra were collected via this search coil. See the 'B_Quality' variable and the 'Quality_note' for issues regarding Bu_Spectra.

Units
nT^2 Hz^-1
Wave
WaveType
PlasmaWaves
WaveQuantity
ACMagneticField
FrequencyRange
SpectralRange
RadioFrequency
Low
5.62
High
311000
Units
Hz
Parameter #9
Name
Magnetic Data Quality Flags
ParameterKey
B_Quality
Description

Integer combining all data B search coil quality flags, 0 = no issues detected. A bitwise OR'ing of all known issue values for this record. The following issue values are defined. (0x1: SCAN) if this flag is present then the Medium Energy Particles instrument's (D. J. Williams) scan platform is in operation, (0x2: Z-MEAS) if this flag is present internally generated signals are being applied to the search coil antennas.

Support
SupportQuantity
Other