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Voyager 1 High Resolution Plasma Data

ResourceID
spase://NASA/NumericalData/Voyager1/Plasma/PT12S

Description

The plasma investigation made use of two Faraday-cup detectors, one pointed along the earth-spacecraft line and one at right angles to this line. The earth-pointing detector determined the macroscopic properties of the plasma ions, obtaining accurate values of their velocity, density, and pressure. Three sequential energy scans were employed with (delta E)/E equal to 20, 7.2, and 1.8%, allowing a coverage from subsonic to highly supersonic flow. The side-looking Faraday cup measured electrons in the energy range from 5 eV to 1 keV. The plasma parameters are obtained by finding the best fit of a convected isotropic Maxwellian distribution to the data. One sigma errors are typically less than 0.5% in the speed and VR, less than 5% for the density and thermal speed, and vary greatly for VT and VN. Sampling times range from 12 to 192 sec., with sampling generally more frequent early in the mission. The velocity components are given in the RTN coordinate system, where R is radially outward, T is in a plane parallel to the solar equatorial plane and positive in the direction of solar rotation, and N completes a right-handed system.

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Details

Version:2.2.9

NumericalData

ResourceID
spase://NASA/NumericalData/Voyager1/Plasma/PT12S
ResourceHeader
ResourceName
Voyager 1 High Resolution Plasma Data
ReleaseDate
2020-07-07 21:15:55Z
Description

The plasma investigation made use of two Faraday-cup detectors, one pointed along the earth-spacecraft line and one at right angles to this line. The earth-pointing detector determined the macroscopic properties of the plasma ions, obtaining accurate values of their velocity, density, and pressure. Three sequential energy scans were employed with (delta E)/E equal to 20, 7.2, and 1.8%, allowing a coverage from subsonic to highly supersonic flow. The side-looking Faraday cup measured electrons in the energy range from 5 eV to 1 keV. The plasma parameters are obtained by finding the best fit of a convected isotropic Maxwellian distribution to the data. One sigma errors are typically less than 0.5% in the speed and VR, less than 5% for the density and thermal speed, and vary greatly for VT and VN. Sampling times range from 12 to 192 sec., with sampling generally more frequent early in the mission. The velocity components are given in the RTN coordinate system, where R is radially outward, T is in a plane parallel to the solar equatorial plane and positive in the direction of solar rotation, and N completes a right-handed system.

Acknowledgement
Please acknowledge John W. Belcher (P.I.)
Contacts
RolePersonStartDateStopDateNote
1.PrincipalInvestigatorspase://SMWG/Person/John.W.Belcher
PriorIDs
spase://VHO/NumericalData/Voyager1/Plasma/PT12S
spase://VSPO/NumericalData/Voyager1/Plasma/PT12S
AccessInformation
RepositoryID
Availability
Online
AccessRights
Open
AccessURL
Name
FTPS from SPDF (not with most browsers)
URL
AccessURL
Name
HTTPS from SPDF
URL
Description

In CDF via HTTP from SPDF

Format
Text
AccessInformation
RepositoryID
Availability
Online
AccessRights
Open
AccessURL
Name
high resolution ASCII data via ftp from MIT
URL
Format
Text
InstrumentIDs
MeasurementType
ThermalPlasma
TemporalDescription
TimeSpan
StartDate
1977-01-01 00:00:00
StopDate
1980-12-31 00:00:00
Cadence
PT12S
ObservedRegion
Heliosphere.Outer
ObservedRegion
Heliosphere.NearEarth
Parameter #1
Name
Year
ParameterKey
Column_1
Description

Year

Support
SupportQuantity
Temporal
Parameter #2
Name
Day of Year
ParameterKey
Column_2
Description

Day of year (day 1 is Jan. 1)

Support
SupportQuantity
Temporal
Parameter #3
Name
Decimal Hour
ParameterKey
Column_3
Support
SupportQuantity
Temporal
Parameter #4
Name
Proton Speed
ParameterKey
Column_4
Units
km/s
Particle
ParticleType
Proton
ParticleQuantity
FlowSpeed
Parameter #5
Name
Proton Density
ParameterKey
Column_5
Units
cm-3
Particle
ParticleType
Proton
ParticleQuantity
NumberDensity
Parameter #6
Name
Proton Thermal Speed
ParameterKey
Column_6
Caveats
proton temperature in eV = .0052 times the square of the thermal speed
Units
km/s
Particle
ParticleType
Ion
ParticleQuantity
ThermalSpeed
Parameter #7
Name
Velocity R Component
ParameterKey
Column_7
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
RTN
Particle
ParticleType
Proton
Qualifier
Component.I
ParticleQuantity
Velocity
Parameter #8
Name
Velocity T Component
ParameterKey
Column_8
Caveats
WARNING: this parameter is often NOT reliable after 1989
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
RTN
Particle
ParticleType
Proton
Qualifier
Component.J
ParticleQuantity
Velocity
Parameter #9
Name
Velocity N Component
ParameterKey
Column_9
Caveats
WARNING: this parameter is often NOT reliable after 1989
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
RTN
Particle
ParticleType
Proton
Qualifier
Component.K
ParticleQuantity
Velocity