Data Description

This page summarizes information about the selected resource and its origin based on SPASE metadata.

Table of Contents

  1. Product
  2. Repository
  3. Instrument
  4. Observatory
  5. Persons

SPASE version 2.0.0

Numerical Data Product: ACE Solar Wind Electron Proton Alpha Monitor (SWEPAM) 64-Second Level 2 Data in CDF Format

Resource ID
spase://VHO/NumericalData/ACE/SWEPAM/CDF_PT64S Get XML
Name
ACE Solar Wind Electron Proton Alpha Monitor (SWEPAM) 64-Second Level 2 Data in CDF Format
Description

Solar Wind Ion parameters from ACE/SWEPAM. Level 2 data, 64-second averages.

Additional information
ACE SWEPAM Level 2 data Home Page

ACE Science Center site hosting instrument information, data release notes, as well as web utilities for plotting and downloading data

Rules of use, and caveats

ACE level 2 data rules of use, and caveats

Acknowledgement

Please acknowledge the ACE/SWEPAM instrument team and the ACE Science Center

Contact
Role Person
1. Technical contact Ruth Skoug Get XML
Release date
2009-05-20 19:08:29
Repository
Name
CDAWeb Data Repository FTP Interface Get XML
Availability
Online
Access rights
Open
URL
ftp://cdaweb.gsfc.nasa.gov/pub/istp/ace/swe_h0/

FTP repository of 64-second ACE SWEPAM data in CDF format at CDAWeb

Format
CDF
Provider processing level
Level 2
Provider resource name
ACE SWEPAM Level 2 Data, 16-second averages, in CDF Format
Provider version
9
Instrument
Solar Wind Electron, Proton and Alpha Monitor (SWEPAM) Get XML
Measurement type
Thermal plasma
Temporal description
Start date
1998-02-04 00:00:12
Relative stop date
2 months ago
Cadence
1 minute 4 seconds
Observed regions
Heliosphere.NearEarth
Caveats

The quality of ACE level 2 data is such that it is suitable for serious scientific study. However, to avoid confusion and misunderstanding, it is recommended that users consult with the appropriate ACE team members before publishing work derived from the data. The ACE team has worked hard to ensure that the level 2 data are free from errors, but the team cannot accept responsibility for erroneous data, or for misunderstandings about how the data may be used. This is especially true if the appropriate ACE team members are not consulted before publication. At the very least, preprints should be forwarded to the ACE team before publication.

↑

Parameters

Parameter #1

Name
Time
Parameter key
Epoch
Description

Number of milliseconds since CDF_EPOCH: 0000-01-01T00:00:00.000. Timestamp marks beginning of interval

Units
ms
Conversion to SI units
1e-3>s
Valid minimum
1996-01-01T00:00:00.000Z
Valid maximum
2020-01-01T00:00:00.000Z
Fill value
-1.0E31
Parameter type
Temporal

Parameter #2

Name
Time PB5
Parameter key
Time_PB5
Description

Time of observation in year, day of year, and milliseconds. Timestamp marks beginning of interval

Structure
Size
3
Elements
Index Name Units Valid min Valid max Fill value
1 Year year 1997 2020 -2147483648
2 Day of year day 1 366 -2147483648
3 Elapsed milliseconds of day msec 0 86401000 -2147483648
Parameter type
Temporal

Parameter #3

Name
Proton Number density
Parameter key
Np
Description

Solar Wind Proton Number Density, scalar

Caveats

Np is the proton number density in units of cm-3, as calculated by integrating the ion distribution function.

Units
cm^-3
Valid minimum
0.0
Valid maximum
200.0
Fill value
-1.0E31
Particle type
Proton
Quantity
Number density
Qualifier
Moment

Parameter #4

Name
Solar Wind Proton Speed
Parameter key
Vp
Description

Solar Wind Bulk Speed

Caveats

Vp is the solar wind proton speed, or more generally just the solar wind (bulk) speed. It is obtained by integrating the ion (proton) distribution function.

Units
km/s
Valid minimum
0.0
Valid maximum
2500.0
Fill value
-1.0E31
Particle type
Proton
Quantity
Velocity
Qualifier
Moment
Scalar

Parameter #5

Name
Proton Temperature
Parameter key
Tpr
Description

radial component of the proton temperature

Caveats

The radial component of the proton temperature is the (1,1) component of the temperature tensor, along the radial direction. It is obtained by integration of the ion (proton) distribution function.

Units
Kelvin
Valid minimum
1000.0
Valid maximum
1100000.0
Fill value
-1.0E31
Particle type
Proton
Quantity
Temperature
Qualifier
Moment

Parameter #6

Name
alpha/proton ratio
Parameter key
alpha_ratio
Description

alpha to proton density ratio

Caveats

Alpha ratio (Na/Np) - is the ratio of the number density of helium++ ions to the number density of protons.

Valid minimum
0.0
Valid maximum
10.0
Fill value
-1.0E31
Particle type
AlphaParticle
Proton
Quantity
Number density
Qualifier
Ratio

Parameter #7

Name
Solar Wind Velocity (GSE)
Parameter key
V_GSE
Description

Solar Wind Velocity in GSE cartesian coordinates, 64-second average

Caveats

Solar Wind Velocity in GSE coords, 64-second average

Units
km/s
Coordinate system
Cartesian GSE
Structure
Size
3
Elements
Index Name Component Units Valid min Valid max Fill value
1 VX (GSE) I -2000.0 0.0 -1.0E31
2 VY (GSE) J -900.0 900.0 -1.0E31
3 VZ (GSE) K -900.0 900.0 -1.0E31
Particle type
Proton
Quantity
Velocity
Qualifier
Moment
Vector

Parameter #8

Name
Solar Wind Velocity (RTN)
Parameter key
V_RTN
Description

Solar Wind Velocity in RTN cartesian coordinates, 64-second average

Caveats

Solar Wind Velocity in RTN cartesian coordinates, 64-second average

Units
km/s
Coordinate system
Cartesian RTN
Structure
Size
3
Elements
Index Name Component Units Valid min Valid max Fill value
1 VR (RTN) I 0.0 2000.0 -1.0E31
2 VT (RTN) J -900.0 900.0 -1.0E31
3 VN (RTN) K -900.0 900.0 -1.0E31
Particle type
Proton
Quantity
Velocity
Qualifier
Moment
Vector

Parameter #9

Name
Solar Wind Velocity (GSM)
Parameter key
V_GSM
Description

Solar Wind Velocity in GSM cartesian coordinates, 64-second average

Caveats

Solar Wind Velocity in GSM ccartesian coordinates, 64-second average

Units
km/s
Coordinate system
Cartesian GSM
Structure
Size
3
Elements
Index Name Component Units Valid min Valid max Fill value
1 VX (GSM) I -1800.0 0.0 -1.0E31
2 VY (GSM) J -900.0 900.0 -1.0E31
3 VZ (GSM) K -900.0 900.0 -1.0E31
Particle type
Proton
Quantity
Velocity
Qualifier
Moment
Vector

Parameter #10

Name
S/C position in GSE
Parameter key
SC_pos_GSE
Description

ACE s/c position in GSE coordinates

Units
km
Conversion to SI units
1e3>m
Coordinate system
Cartesian GSE
Structure
Size
3
Elements
Index Name Component Units Valid min Valid max Fill value
1 X GSE I -2000000.0 2000000.0 -1.0E31
2 Y GSE J -2000000.0 2000000.0 -1.0E31
3 Z GSE K -2000000.0 2000000.0 -1.0E31
Parameter type
Positional

Parameter #11

Name
S/C position in GSM
Parameter key
SC_pos_GSM
Description

ACE s/c position in GSM coordinates

Caveats
Units
km
Conversion to SI units
1e3>m
Coordinate system
Cartesian GSM
Structure
Size
3
Elements
Index Name Component Units Valid min Valid max Fill value
1 X GSM I -2000000.0 2000000.0 -1.0E31
2 Y GSM J -2000000.0 2000000.0 -1.0E31
3 Z GSM K -2000000.0 2000000.0 -1.0E31
Parameter type
Positional
↑

SPASE version 2.0.0

Instrument: Solar Wind Electron, Proton and Alpha Monitor (SWEPAM)

Instrument ID
spase://SMWG/Instrument/ACE/SWEPAM Get XML
Name
Solar Wind Electron, Proton and Alpha Monitor (SWEPAM)
Alternate name
SWEPAM
Description

The Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) instrument sensors measure solar wind electrons at 1 - 900 eV energy and ions at 0.26 - 35 keV. The instrument consists of separate electron and ion analyzers originally built as spares for the Ulysses mission. The two sensors both utilizes curved-plate electrostatic analyzers (ESAs) consisting of spherical sections cut into sectors. Biased channel electron multipliers (CEMS) are spaced along the exit apertures of the ESAs for ion and electron detection. Different CEMs sample different portions of the fan-shaped fields of view. The ion sensor consists of a 105-degree bending angle ESA with an average radius of 100 mm and a plate spacing of 2.84 mm. Sixteen CEMs contiguously spaced along the exit gap of the ESA give about 5-degree polar angular resolution over the approximately 70-degree opening angle of the acceptance fan. The electron sensor consists of a 120-degree bending angle ESA with an average radius of 41.9 mm and a plate spacing of 3.5 mm. Seven large-funnel CEMs along the exit gap give about 20-degree angular resolution over a 160-degree fan angle. The sensor geometric factors are 0.002 cm2-sr for isotropic response and 0.009 cm2 for unidirectional. Energy resolution is five percent for ions and twelve percent for electrons. SWEPAM data consists of ion and electron rates collected at each energy/charge (E/Q) step, polar lock direction, and azimuthal spin direction. A single spacecraft spin period of 12 seconds is sufficient for accumulation of count matricies to fully calculate the electron and ion distribution functions from which bulk moments (solar wind speed, density, temperature) can be calculated by ground data processing. Accumulated counts will actually be summed over one-minute intervals for increased statistical accuracy and for reduction of telemetry requirements. Limited data from single spins will be provided for timing of the passage of transient solar wind structures.

Additional information
SWEPAM home page at LANL

Information about the SWEPAM instrument, with links to data and other documentation

NSSDC's Master Catalog

Information about the Solar Wind Electron, Proton and Alpha Monitor (SWEPAM) experiment on the ACE mission.

Contact
Role Person
1. CoInvestigator Dr. David J. McComas Get XML
2. Technical contact Ruth Skoug Get XML
Release date
2009-05-20 21:10:13
Prior ID
spase://SMWG/instrument/1997-045A-07
Instrument type
Electrostatic Analyser
Investigation name
Solar Wind Electron, Proton and Alpha Monitor (SWEPAM) on ACE
Observatory
ACE Get XML
↑

SPASE version 2.0.0

Observatory: ACE

Observatory ID
spase://SMWG/Observatory/ACE Get XML
Name
ACE
Alternate name
Advanced Composition Explorer
1997-045A
Explorer 71
Description

The objective of the Advanced Composition Explorer (ACE) is to collect observations of particles of solar, interplanetary, interstellar, and galactic origins, spanning the energy range from that of KeV solar wind ions to galactic cosmic ray nuclei up to 600 MeV/nucleon. Definitive studies will be made of the abundances of essentially all isotopes from H to Zn (Z = 1-30), with exploratory isotope studies extending to Zr (Z = 40). The ACE payload includes six high resolution spectrometers, each designed to provide the optimum charge, mass, or charge-state resolution in its particular energy range. Each spectrometer has a geometry factor optimized for the expected flux levels, so as to provide a collecting power greater by a factor of 10-1000 times that of previous or planned experiments. The payload also includes three additional instruments of standard design to monitor energetic electrons, H and He ions, and a magnetometer. The ACE spacecraft is based on the design of the Charge Composition Explorer, built at JHU/APL for the Active Magnetospheric Particle Tracer Explorer (AMPTE) program. The spacecraft spin axis is pointed towards the Sun to within +/- 20 degrees, and it occupies a halo orbit about the L1 Earth-Sun libration point. Powered by solar cells, the spacecraft has a design life of at least five years, and it returns data in daily tape recorder dumps, received through NASA JPL's Deep Space Network and initially processed at NASA-GSFC. The average data telemetry rate is 6.7 Kbs.

Additional information
ACE Home Page

ACE mission home page at Caltech with data download

NSSDC's Master Catalog

Information about the ACE mission

Contact
Role Person
1. Principal investigator Prof. Edward C. Stone, Jr. Get XML
Release date
2009-05-20 20:00:12
Prior ID
spase://vspo/observatory/2
Location
Region
Heliosphere.Inner
Heliosphere.NearEarth
↑

SPASE version 2.0.0

Person: Ruth Skoug

Name
Ruth Skoug
Organization
LANL
Person ID
spase://SMWG/Person/Ruth.Skoug Get XML
↑

SPASE version 2.0.0

Person: Dr. Robert E. McGuire

Name
Dr. Robert E. McGuire
Organization
NASA Goddard Space Flight Center
Address
Code 672, Greenbelt, MD 20771, USA
Email
mcguire@mail630.gsfc.nasa.gov
Phone
1-301-286-7794
Person ID
spase://SMWG/Person/Robert.E.McGuire Get XML
Release date
2007-05-30 15:25:24
↑

SPASE version 2.0.0

Person: Dr. David J. McComas

Name
Dr. David J. McComas
Organization
Southwest Research Institute
Person ID
spase://SMWG/Person/David.J.McComas Get XML
↑

SPASE version 2.0.0

Person: Prof. Edward C. Stone, Jr.

Name
Prof. Edward C. Stone, Jr.
Organization
California Institute of Technology
Email
ecs@srl.caltech.edu
Phone
+1-626-395-8321
Person ID
spase://SMWG/Person/Edward.C.Stone.Jr Get XML
Release date
2001-04-02 00:00:00
↑

SPASE version 1.2.0

Repository: CDAWeb Data Repository FTP Interface

Repository ID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb Get XML
Name
CDAWeb Data Repository FTP Interface
Description

Coordinated Data Analysis Web (CDAWeb) supports not only interactive plotting of variables from multiple instruments on multiple investigations simultaneously on arbitrary, user-defined time-scales. It also supports data retrieval in various formats using its interactive web interface or ftp service.

Additional information
CDAWeb Home Page

Coordinated Data Analysis Web (CDAWeb) home page at Space Physics Data Facility of the NASA Goddard Space Flight Center.

Contact
Role Person
1. Project scientist Dr. Robert E. McGuire Get XML
Release date
2008-08-26 21:14:34
Prior ID
spase://VMO/Repository/CDAWeb
↑