HDPWS

ResourceID

spase://NASA/NumericalData/Voyager2/MAG/CDF/PT1H

Description

This data set includes the Voyager spacecraft number (1 or 2), the date-time in decimal year (90.00000 is day 1 of 1990), the magnetic field strength, F1, computed from high-resolution magnitudes, the elevation and azimuth angles in heliographic (RTN) coordinates, and the magnetic field strength, F2, computed from 1-hr averages of the components. The vector components of B can be computed from F2 and the two angles. The elevation angle is the latitude angle above or below the solar equatorial plane, and the azimuth angle is in the direction orbital motion around the Sun from the projection of the Sun-to-spacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Sci. Rev., 21 (3), 235-257, 1977. At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al., 1977). At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis, which is nearly parallel to the radius vector to the Sun, at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. (1994) and in Appendix A of Burlaga et al. (2002). References: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Science Reviews, 21 (3), 235-257, 1977. Burlaga, L.F., Merged interaction regions and large-scale magnetic field fluctuations during 1991 - Voyager-2 observations, J. Geophys. Res., 99 (A10), 19341-19350, 1994. Burlaga, L.F., N.F. Ness, Y.-M. Wang, and N.R. Sheeley, Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. Ness et al., 1973.
Coordinate Systems: Interplanetary magnetic field studies make use of two important coordinate systems, the Heliographic Inertial (HGI) coordinate system and the Heliographic (HG) coordinate system.
The HGI coordinate system is used to define the spacecraft's position. The HGI system is defined with its origin at the Sun. There are three orthogonal axes, X(HGI), Y(HGI), and Z(HGI). The Z(HGI) axis points northward along the Sun's spin axis. The X(HGI)-Y(HGI) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(HGI) axis. The X(HGI) axis drifts slowly with time, approximately one degree per 72 years.
The magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (HGI origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(HGI)-Y(HGI) plane as well. The Z(HG) axis is chosen to complete the orthonormal triad.
An excellent reference guide with diagrams explaining the HGI and HG systems may be found in L.F. Burlaga, MHD Processes in the Outer Heliosphere, Space Sci. Rev., 39, 255-316, 1984.

Version:2.2.8

ResourceID

spase://NASA/NumericalData/Voyager2/MAG/CDF/PT1H

ResourceHeader

ResourceName

Voyager 2 1-hr Averaged Triaxial Fluxgate Magnetometer (MAG) Interplanetary Magnetic Field in CDF Format

ReleaseDate

2020-07-07 21:15:58Z

Description

This data set includes the Voyager spacecraft number (1 or 2), the date-time in decimal year (90.00000 is day 1 of 1990), the magnetic field strength, F1, computed from high-resolution magnitudes, the elevation and azimuth angles in heliographic (RTN) coordinates, and the magnetic field strength, F2, computed from 1-hr averages of the components. The vector components of B can be computed from F2 and the two angles. The elevation angle is the latitude angle above or below the solar equatorial plane, and the azimuth angle is in the direction orbital motion around the Sun from the projection of the Sun-to-spacecraft axis into the solar equatorial plane. The Voyager MAG experiment and coordinates are further described in the following publication: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Sci. Rev., 21 (3), 235-257, 1977. At the time of experiment proposal, it was expected that the required accuracy of the measurements would be 0.1 nT, determined by the combined noise of the sensors and the spacecraft field. The spacecraft magnetic field at the outboard magnetic field sensor, referred to as the primary unit, was expected to be 0.2 nT and highly variable, consistent with current estimates. Hence, the dual magnetometer design (Ness et al., 1971, 1973; Behannon et al., 1977). At distances > 40 AU, the heliospheric magnetic fields are generally much weaker than 0.4 nT; the average magnetic field strength near 40 AU and 85 AU is about 0.15 nT and 0.05 nT, respectively. The use of roll calibrations lasting about 6 hours permits determination of the effective zero levels for the two independent magnetic axes that are perpendicular to the roll axis, which is nearly parallel to the radius vector to the Sun, at intervals of about 3 months. There is no roll calibration for the third magnetic axis. Comparison of the two derived magnetic vectors from the two magnetometers permits validation of the primary magnetometer data with an accuracy of 0.02 to 0.05 nT. A discussion of the uncertainties that must be considered when using these data is given in the Appendix of Burlaga et al. (1994) and in Appendix A of Burlaga et al. (2002). References: Behannon, K.W., M.H. Acuna, L.F. Burlaga, R.P. Lepping, N.F. Ness, and F.M. Neubauer, Magnetic-Field Experiment for Voyager-1 and Voyager-2, Space Science Reviews, 21 (3), 235-257, 1977. Burlaga, L.F., Merged interaction regions and large-scale magnetic field fluctuations during 1991 - Voyager-2 observations, J. Geophys. Res., 99 (A10), 19341-19350, 1994. Burlaga, L.F., N.F. Ness, Y.-M. Wang, and N.R. Sheeley, Jr., Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23, J. Geophys. Res., 107 (A11), 1410, 2002. Ness, N., K.W. Behannon, R. Lepping, and K.H. Schatten, J. Geophys. Res., 76, 3564, 1971. Ness et al., 1973.
Coordinate Systems: Interplanetary magnetic field studies make use of two important coordinate systems, the Heliographic Inertial (HGI) coordinate system and the Heliographic (HG) coordinate system.
The HGI coordinate system is used to define the spacecraft's position. The HGI system is defined with its origin at the Sun. There are three orthogonal axes, X(HGI), Y(HGI), and Z(HGI). The Z(HGI) axis points northward along the Sun's spin axis. The X(HGI)-Y(HGI) plane lays in the solar equatorial plane. The intersection of the solar equatorial plane with the ecliptic plane defines a line, the longitude of the ascending node, which is taken to be the X(HGI) axis. The X(HGI) axis drifts slowly with time, approximately one degree per 72 years.
The magnetic field orientation is defined in relation to the spacecraft. Drawing a line from the Sun's center (HGI origin) to the spacecraft defines the X axis of the HG coordinate system. The HG coordinate system is defined with its origin centered at the spacecraft. Three orthogonal axes are defined, X(HG), Y(HG), and Z(HG). The X(HG) axis points radially away from the Sun and the Y(HG) axis is parallel to the solar equatorial plane and therefore parallel to the X(HGI)-Y(HGI) plane as well. The Z(HG) axis is chosen to complete the orthonormal triad.
An excellent reference guide with diagrams explaining the HGI and HG systems may be found in L.F. Burlaga, MHD Processes in the Outer Heliosphere, Space Sci. Rev., 39, 255-316, 1984.

Acknowledgement

Please acknowledge the Principal Investigator, Norman F. Ness of the Bartol Research Institute, University of Delaware, and the NASA National Space Science Data Center (NSSDC) for usage of data from this site in publications and presentations.

Contacts

Role | Person | StartDate | StopDate | Note | |
---|---|---|---|---|---|

1. | PrincipalInvestigator | spase://SMWG/Person/Norman.F.Ness | |||

2. | MetadataContact | spase://SMWG/Person/Robert.E.McGuire | |||

3. | MetadataContact | spase://SMWG/Person/Lee.Frost.Bargatze |

PriorIDs

spase://VSPO/NumericalData/Voyager2/MAG/CDF/PT1H

AccessInformation

RepositoryID

Availability

Online

AccessRights

Open

AccessURL

Name

FTPS from SPDF (not with most browsers)

URL

Description

In CDF via ftp from SPDF.

AccessURL

Name

HTTPS from SPDF

URL

Description

In CDF via http from SPDF.

Format

CDF

Encoding

None

Acknowledgement

Please acknowledge the Principal Investigator, Norman F. Ness of the Bartol Research Institute, University of Delaware, and the NASA National Space Science Data Center (NSSDC) for usage of data from this site in publications and presentations. Please acknowledge the data providers and CDAWeb when using these data.

ProcessingLevel

Calibrated

InstrumentIDs

MeasurementType

MagneticField

TemporalDescription

TimeSpan

StartDate

1990-01-01 00:00:00.000

StopDate

1990-12-31 17:59:59.416

Cadence

PT1H

ObservedRegion

Heliosphere

ObservedRegion

Heliosphere.Outer

ObservedRegion

Heliosphere.Heliosheath

Parameter #1

Name

Time, Beginning of Interval

ParameterKey

Epoch

Description

Time, Beginning of Interval

Caveats

This parameter exhibits an increasing monotonic progression.

Cadence

PT1H

Units

ms

UnitsConversion

1e-3>s

RenderingHints

AxisLabel

Epoch

ValueFormat

E14.8

ScaleMin

6.2987652219904e+13

ScaleMax

6.3745034619904e+13

ScaleType

LinearScale

ValidMin

01-Jan-1996 00:00:00.000

ValidMax

01-Jan-2020 00:00:00.000

FillValue

-1.0e+31

Support

SupportQuantity

Temporal

Parameter #2

Name

Spacecraft Identification

Set

Time series defined by using: EPOCH

ParameterKey

Spacecraft

Description

Spacecraft Identification. 1 for Voyager 1, 2 for Voyager 2, List only

Cadence

PT1H

RenderingHints

AxisLabel

Spacecraft

ValueFormat

I1

ValidMin

1

ValidMax

2

FillValue

-128

Support

SupportQuantity

Other

Parameter #3

Name

Decimal Year

Set

Time series defined by using: EPOCH

ParameterKey

Decimal_Year

Description

Decimal Year, 90.00000 is at the Start of Day 1 for Year 1990

Cadence

PT1H

RenderingHints

DisplayType

TimeSeries

AxisLabel

Decimal Year

ValueFormat

F12.8

ValidMin

1.0

ValidMax

367.0

Support

SupportQuantity

Temporal

Parameter #4

Name

B Field Magnitude by Method 1, F1

Set

Time series defined by using: EPOCH

ParameterKey

F1Mag

Description

Magnetic Field Magnitude by Method 1, F1, 1-hr Average of High-Resolution Magnitudes

Caveats

This is the hourly time average of magnitudes from high resolution data.

Cadence

PT1H

Units

nT

UnitsConversion

1e-9>T

RenderingHints

DisplayType

TimeSeries

AxisLabel

F1 Magnitude

ValueFormat

F6.3

ValidMin

0.0

ValidMax

10.0

FillValue

999.0

Field

Qualifier

Magnitude

Qualifier

Average

FieldQuantity

Magnetic

Parameter #5

Name

Elevation Angle

Set

Time series defined by using: EPOCH

ParameterKey

elevation

Description

The Elevation Angle in Heliographic (HG) RTN Coordinates

Caveats

This is the latitude angle above or below the solar equatorial plane.

Cadence

PT1H

Units

°

UnitsConversion

0.0174532925>rad

CoordinateSystem

CoordinateRepresentation

Spherical

CoordinateSystemName

HGI

RenderingHints

DisplayType

TimeSeries

AxisLabel

elevation angle

ValueFormat

F6.1

ValidMin

-90.0

ValidMax

90.0

FillValue

999.0

Support

Qualifier

DirectionAngle.ElevationAngle

SupportQuantity

Positional

Parameter #6

Name

Azimuthal Angle

Set

Time series defined by using: EPOCH

ParameterKey

azimuth

Description

The Azimuthal Angle in Heliographic (HG) RTN Coordinates

Caveats

This is the longitude angle in the direction of orbital motion around the Sun from the Sun-to-spacecraft direction.

Cadence

PT1H

Units

°

UnitsConversion

0.0174532925>rad

CoordinateSystem

CoordinateRepresentation

Spherical

CoordinateSystemName

HGI

RenderingHints

DisplayType

TimeSeries

AxisLabel

elevation angle

ValueFormat

F6.1

ValidMin

0.0

ValidMax

360.0

FillValue

999.0

Support

Qualifier

DirectionAngle.AzimuthAngle

SupportQuantity

Positional

Parameter #7

Name

B Field Magnitude by Method 2, F2

Set

Time series defined by using: EPOCH

ParameterKey

F2Mag

Description

Magnetic Field Magnitude by Method 2, F2, 1-hr Average derived from 1-hr Averages of the B1, B2, and B3 Component Data, the value is computed by using sqrt(B1^2+B2^2+B3^2)

Caveats

The vector components are computed from F2mag and the two angles for elevation (latitude) and azimuth (longitude).

Cadence

PT1H

Units

nT

UnitsConversion

1e-9>T

RenderingHints

DisplayType

TimeSeries

AxisLabel

F1 Magnitude

ValueFormat

F6.3

ValidMin

0.0

ValidMax

10.0

FillValue

999.0

Field

Qualifier

Magnitude

Qualifier

Average

FieldQuantity

Magnetic