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SPASE version 2.0.1

Numerical Data Product: IMP 8 MAG PLS 1-min field and plasma data at bow shock nose

Resource ID

spase://VMO/NumericalData/IMP8/Propagated/PT1M

Name

IMP 8 MAG PLS 1-min field and plasma data at bow shock nose

Alternate name

IMP 8 at BSN

Description

Solar wind magnetic field and plasma data at 1-min resolution created from IMP 8 data shifted to the Earth's bow shock nose (BSN).

Additional information

Readme at nssdcftp

Acknowledgement

We acknowledge A.Szabo and R. Lepping of the MAG team, A. Lazarus of the PLS team and J. King and N. Papitashvili of NASA/SPDF and ADNET who created this product.

Contact

	Role	Person
1.	Data producer	Dr. Joseph H. King
2.	Data producer	Dr. Natalia E. Papitashvili

Release date

2009-08-01 00:00:00

Repository #1

Name

SPDF

Availability

Online

Access rights

Open

URL

OMNIWeb: OMNIWeb, 1-min IMP 8

Format

Text

Encoding

None

Repository #2

Name

SPDF

Availability

Online

Access rights

Open

URL

nssdcftp: FTP path at SPDF/NSSDC

Format

Text

Encoding

None

File size

129 MB per 1 year

Provider resource name

IMP 8 MAG PLS Data at BSN

Instruments

IMP-8 Magnetic Field Experiment

IMP 8 Solar Plasma Faraday Cup

Measurement type

Magnetic field

Thermal plasma

Temporal description

Start date: 1994-01-01 00:00:00
Stop date: 2000-06-10 00:00:00
Cadence: 1 minute

Observed regions

Heliosphere.NearEarth

↑

Parameters

Parameter #1

Name

Magnetic field vector, GSE

Description

Magnetic field vector, GSE

Cadence

1 minute

Units

Coordinate system

Cartesian GSE

Structure

Size

Description

Magnetic field vector, GSE

Elements

Index	Name	Parameter key	Units
1	Bx(GSE)	Column13	nT
2	By(GSE)	Column14	nT
3	Bz(GSE)	Column15	nT

Quantity

Magnetic field

Qualifier

Component

Average

Parameter #2

Name

Magnetic field vector, GSM

Description

Magnetic field vector, GSM

Cadence

1 minute

Units

Coordinate system

Cartesian GSM

Structure

Size

Description

Magnetic field vector, GSM

Elements

Index	Name	Parameter key	Units
1	Bx(GSM)	Column13	nT
2	By(GSM)	Column16	nT
3	Bz(GSM)	Column17	nT

Quantity

Magnetic field

Qualifier

Component

Average

Parameter #3

Name: Magnetic field magnitude
Parameter key: Column12
Description: Magnetic field magnitude
Cadence: 1 minute
Units: nT
Quantity: Magnetic field
Qualifier: Magnitude; Average

Parameter #4

Name: Magnetic field vector standard deviation
Parameter key: Column21
Description: Square root of sum of variances of component averages.
Cadence: 1 minute
Units: nT
Quantity: Magnetic field
Qualifier: Variance; Component

Parameter #5

Name: Magnetic field magnitude standard deviation
Parameter key: Column20
Description: Standard deviation in the average of magnetic field magnitudes
Cadence: 1 minute
Units: nT
Quantity: Magnetic field
Qualifier: Variance; Magnitude

Parameter #6

Name: Flow speed
Parameter key: Column23
Description: Flow speed of the solar wind
Cadence: 1 minute
Units: km/s
Particle type: Proton
Quantity: Velocity
Qualifier: Magnitude

Parameter #7

Name

Flow velocity vector

Description

Flow velocity vector, 3 GSE cartesian components

Cadence

1 minute

Units

km/s

Coordinate system

Cartesian GSE

Structure

Size

Description

Flow velocity vector, GSE

Elements

Index	Name	Parameter key	Units
1	Vx(GSE)	Column24	km/s
2	Vy(GSE)	Column25	km/s
3	Vz(GSE)	Column26	km/s

Particle type

Proton

Quantity

Velocity

Qualifier

Vector

Parameter #8

Name: Proton density
Parameter key: Column27
Description: Proton density
Cadence: 1 minute
Units: no./cc
Particle type: Proton
Quantity: Number density

Parameter #9

Name: Proton temperature
Parameter key: Column28
Description: Proton scalar temperature
Cadence: 1 minute
Units: deg K
Particle type: Proton
Quantity: Temperature

Parameter #10

Name

Spacecraft position

Description

Position of IMP 8 spacecraft, GSE cartesian components

Cadence

1 minute

Units

Coordinate system

Cartesian GSE

Structure

Size

Description

Spacecraft position vector, GSE

Elements

Index	Name	Parameter key	Units
1	X(IMP8,GSE)	Column29	Re
2	Y(IMP8,GSE)	Column30	Re
3	Z(IMP8,GSE)	Column31	Re

Parameter type

Positional

Parameter #11

Name

Bow shock nose position

Description

Bow shock nose position, as computed from observed data and models, 3 cartesian components

Cadence

1 minute

Units

Coordinate system

Cartesian GSE

Structure

Size

Description

Bow shock nose (BSN) position vector, GSE

Elements

Index	Name	Parameter key	Units
1	X(BSN,GSE)	Column32	Re
2	Y(BSN,GSE)	Column33	Re
3	Z(BSN,GSE)	Column34	Re

Parameter type

Other

Parameter #12

Name: Mean time shift
Parameter key: Column08
Description: Time shift from observation time to bow shock nose (BSN) arrival time, as averaged over all 15-16 sec B values with BSN arrival times in minute of interest
Cadence: 1 minute
Units: sec
Parameter type: Other

Parameter #13

Name

Numbers of points in field and plasma averages

Description

Numbers of fine scale points in field and plasma averages

Cadence

1 minute

Structure

Size

Description

Numbers of fine scale points in field and plasma averages

Elements

Index	Name	Parameter key
1	Numbers of fine scale points in field averages	Column05
2	Numbers of fine scale points in plasma averages	Column22

Parameter type

Other

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SPASE version 2.0.0

Instrument: IMP-8 Magnetic Field Experiment

Instrument ID

spase://SMWG/Instrument/IMP8/MAG

Name

IMP-8 Magnetic Field Experiment

Alternate name

IMP8 MAG

Description

The magnetic field experiment on the IMP-8 spacecraft utilizes a tri-axial fluxgate (saturable inductor) magnetometer. The instrument originally had three, automatically determined, ranges, ±12 nT, ±36 nT, and ±108 nT, full scale. Because of a range-change circuit failure occurring in early July 1975, the experiment was commanded into a fixed ±36 nT range on July 11, 1975 at 12:55:09 UT and has been in that range ever since. The measurements are A-to-D converted onboard, to an 8-bit resolution, yielding ±0.14 nT quantization sensitivity, which is larger than the intrinsic sensor noise level of 0.025 nT RMS. The data from the two-bit (per component) adaptive delta modulator, incorporated into the instrument, and applied to the intrinsic sample rate of 25 vectors/sec., was never utilized, and hence the rate of the full (8-bit) vector words, which occur every 320 ms, represents the effective sample period of the instrument. The sampling rate is synchronized to the spacecraft clock; the basic spacecraft clock frequency is 6.4 kHz. The sensor unit is mounted on the end of a boom approximately 4 m from the center of the spacecraft.

Additional information

IMP-8 Magnetometer Home Page: A web site hosting IMP-8 magnetic experiment instrument information as well as web utilities for plotting and downloading data.
NSSDC's Master Catalog: Information about the Magnetic Field Experiment experiment on the IMP 8 mission.

Acknowledgement

User will acknowledge the IMP-8 magnetometer team in any publication resulting from the use of these data.

Contact

	Role	Person
1.	Principal investigator	Dr. Adam Szabo

Release date

2009-05-20 21:10:02

Instrument type

Magnetometer

Investigation name

Magnetic Field Experiment

Observatory

IMP 8

Caveats

↑

SPASE version 2.0.0

Instrument: IMP 8 Solar Plasma Faraday Cup

Instrument ID

spase://SMWG/Instrument/IMP8/PLS

Name

IMP 8 Solar Plasma Faraday Cup

Alternate name

IMP 8 PLS

IMP 8 PLA

1973-078A-02

Description

A modulated split-collector Faraday cup, perpendicular to the spacecraft spin axis, was used to study the directional intensity of positive ions and electrons in the solar wind, transition region, and magnetotail. The collector plate split is perpendicular to the spacecraft spin axis in order to measure the flow angle of the ions in a meridional plane; the flow angle in the spacecraft equatorial plane is determined from the fluxes measured as the spacecraft rotates.

Electrons are measured using 21 logarithmically-spaced energy windows covering the energy/charge range between 23 and 1935 volts. Positive ions are studied using 24 energy windows covering the range between 50 and 7000 volts.

The instrument has three operating modes. The tracking mode yields the best time resolution which is about 1 minute. A single energy window is used during a spacecraft rotation. The ion spectrum is obtained in eight spacecraft revolutions using a subset of the energy windows that track the peak of the solar wind. In this mode, fluxes are measured during 11.25-degree sectors of the spacecraft spin while the instrument is looking within the 90 degree sector centered on the sun direction and during 45 degree sectors for the remainder of the rotation. The other modes yield a spectrum using all 24 windows (with the same angular sectors described above) or a spectrum that results from integrating the observed fluxes over 45 degree sectors for the entire spacecraft rotation.

Electron data are obtained in all modes, but are not usually analyzed.

Parameters derived on a routine basis are proton velocity, number density, and temperature (most probable thermal speed). Those parameters are obtained from a non-linear, least-squares fit to the observed fluxes using a convected, isotropic Maxwellian model.

Key Parameters for the Plasma instrument are computed at MIT using Level Zero data that are staged to the ISTP/CDHF approximately two weeks after being received on Earth. Thus the plasma instrument's Key Parameters lag real time by something greater than 2 weeks, but less than four.

Additional information

IMP 8 Home Page
NSSDC's Master Catalog: Information about the Solar Plasma Faraday Cup experiment on the IMP-J mission.

Contact

	Role	Person
1.	Principal investigator	Dr. Alan J. Lazarus

Release date

2009-05-20 21:10:02

Prior ID

spase://SMWG/instrument/1973-078A-02

Instrument type

Faraday Cup

Investigation name

Solar Plasma Faraday Cup on IMP-J

Observatory

IMP 8

↑

SPASE version 2.0.0

Observatory: IMP 8

Observatory ID

spase://SMWG/Observatory/IMP8

Name

IMP 8

Alternate name

IMP-J

Explorer 50

1973-078A

Description

IMP 8 (IMP-J or Explorer 50), the last satellite of the IMP series, was a drum-shaped spacecraft, 135.6 cm across and 157.4 cm high, instrumented for interplanetary and magnetotail studies of cosmic rays, energetic solar particles, plasma, and electric and magnetic fields. Its initial orbit was more elliptical than intended, with apogee and perigee distances of about 45 and 25 earth radii. Its eccentricity decreased after launch. Its orbital inclination varied between 0 deg and about 55 deg with a periodicity of several years. The spacecraft spin axis was normal to the ecliptic plane, and the spin rate was 23 rpm. The data telemetry rate was 1600 bps.

The spacecraft was in the solar wind for 7 to 8 days of every 12.5 day orbit. Telemetry coverage was 90% in the early years, but only 60-70% through most of the 1980's and early 1990's. Coverage returned to the 90% range in the mid to late 1990's.

The objectives of the extended IMP-8 operations were to provide solar wind parameters as input for magnetospheric studies and as a 1-AU baseline for deep space studies, and to continue solar cycle variation studies with a single set of well-calibrated and understood instruments.

In October, 2001, IMP 8 was terminated as an independent mission. Telemetry acquisition resumed after about three months at Canberra only (30-50% coverage), as an adjunct to the Voyager and Ulysses missions. As of August 2005 IMP 8 continued in this mode.

Additional information

IMP-8 Project Information
NSSDC's Master Catalog: Information about the IMP-J mission

Contact

	Role	Person
1.	Project scientist	Dr. Robert E. McGuire

Release date

2009-05-20 20:00:12

Prior ID

spase://vspo/observatory/63

Observatory group

IMP

Location

Region: Earth.Magnetosheath; Earth.Magnetosphere.Magnetotail; Heliosphere.NearEarth

↑

Data Description

Table of Contents

Numerical Data Product: IMP 8 MAG PLS 1-min field and plasma data at bow shock nose

Parameters

Parameter #1

Parameter #2

Parameter #3

Parameter #4

Parameter #5

Parameter #6

Parameter #7

Parameter #8

Parameter #9

Parameter #10

Parameter #11

Parameter #12

Parameter #13

Instrument: IMP-8 Magnetic Field Experiment

Instrument: IMP 8 Solar Plasma Faraday Cup

Observatory: IMP 8

Person: Dr. Joseph H. King

Person: Dr. Natalia E. Papitashvili

Person: Ms. Tamara J. Kovalick

Person: Mr. Robert M. Candey

Person: Dr. Robert E. McGuire

Person: Dr. Adam Szabo

Person: Dr. Alan J. Lazarus

Repository: SPDF

	Role	Person
1.	General contact	Ms. Tamara J. Kovalick
2.	Technical contact	Mr. Robert M. Candey
3.	Project scientist	Dr. Robert E. McGuire