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Wind Solar Wind Experiment (SWE) Averaged Electron Pitch Angle Distribution (12-15s rate)

ResourceID
spase://NASA/NumericalData/Wind/SWE/M0/PT12S

Description

Averaged Wind SWE electron pitch angle data (12-15 seconds rate) from a later mode (post-VEIS-era) of the electron instrument. The electron pitch-angle distribution averages included in this data set are derived from integrating the electron pitch-angle distributions measured by the Wind/SWE electron instrument (see Ogilvie et al., "SWE, a comprehensive plasma instrument for the Wind spacecraft", Space Sci. Rev., 71, 55, 1995). Averages of phase-space density (f) over key regions of the unit sphere (the set of all possible electron velocity directions) are computed from 9s measurements which are usually separated by one or more 3s spin-periods. These quantities are reliable and citable with caution, meaning that the PI advises that the user should discuss their interpretations with a member of the SWE science team before publishing. The following comments are intended to aid in the use and interpretation of the averages reported in this data set. We begin this analysis with a measure of f for each pitch-angle bin, six degrees in width, from 0 degrees (flux nearly parallel to B) to 180 degrees (flux nearly anti-parallel with B). The f values for pitch-angles from 0-90 degrees (parallel streaming) are integrated (with angluar weighting and assumptions of gyrotropy) over this half-sphere, then averaged by dividing out the 2-pi solid angle of the half-sphere; the result being referred to as the 'f_para' average. Similarly, the 'f_perp' (flux nearly perpendicular to B) average is the result of integrating f for pitch-angles from 60-120 degrees (a region also 2-pi in solid angle). Next, the 'f_anti' (flux nearly anti-parallel to B) average covers the half-sphere of "backward" streaming electrons; having pitch-angles from 90-180 degrees. Finally, the 'f_omni' (omni-directional) average provides the integral of f over the full sphere, divided by the full 4-pi solid angle; providing a measure of total electron flux into the region of observation. The above analysis is carried out for each of 13 energy channels: E = 19.34, 38.68, 58.03, 77.37, 96.71, 116.1, 193.4, 290.1, 425.5, 580.3, 773.7, 1006., and 1238. eV. For reference, the electron speeds ( V , in cm/s) corresponding to these energies are reported in this data set. Hence the data set reported here contains: f_para, f_perp, f_anti, f_omni (for each of 13 values of E), and the 13 values of V (constant, included for reference).

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Details

Version:2.2.9

NumericalData

ResourceID
spase://NASA/NumericalData/Wind/SWE/M0/PT12S
ResourceHeader
ResourceName
Wind Solar Wind Experiment (SWE) Averaged Electron Pitch Angle Distribution (12-15s rate)
AlternateName
WI_M0_SWE_v01
ReleaseDate
2020-07-07 21:16:06Z
Description

Averaged Wind SWE electron pitch angle data (12-15 seconds rate) from a later mode (post-VEIS-era) of the electron instrument. The electron pitch-angle distribution averages included in this data set are derived from integrating the electron pitch-angle distributions measured by the Wind/SWE electron instrument (see Ogilvie et al., "SWE, a comprehensive plasma instrument for the Wind spacecraft", Space Sci. Rev., 71, 55, 1995). Averages of phase-space density (f) over key regions of the unit sphere (the set of all possible electron velocity directions) are computed from 9s measurements which are usually separated by one or more 3s spin-periods. These quantities are reliable and citable with caution, meaning that the PI advises that the user should discuss their interpretations with a member of the SWE science team before publishing. The following comments are intended to aid in the use and interpretation of the averages reported in this data set. We begin this analysis with a measure of f for each pitch-angle bin, six degrees in width, from 0 degrees (flux nearly parallel to B) to 180 degrees (flux nearly anti-parallel with B). The f values for pitch-angles from 0-90 degrees (parallel streaming) are integrated (with angluar weighting and assumptions of gyrotropy) over this half-sphere, then averaged by dividing out the 2-pi solid angle of the half-sphere; the result being referred to as the 'f_para' average. Similarly, the 'f_perp' (flux nearly perpendicular to B) average is the result of integrating f for pitch-angles from 60-120 degrees (a region also 2-pi in solid angle). Next, the 'f_anti' (flux nearly anti-parallel to B) average covers the half-sphere of "backward" streaming electrons; having pitch-angles from 90-180 degrees. Finally, the 'f_omni' (omni-directional) average provides the integral of f over the full sphere, divided by the full 4-pi solid angle; providing a measure of total electron flux into the region of observation. The above analysis is carried out for each of 13 energy channels: E = 19.34, 38.68, 58.03, 77.37, 96.71, 116.1, 193.4, 290.1, 425.5, 580.3, 773.7, 1006., and 1238. eV. For reference, the electron speeds ( V , in cm/s) corresponding to these energies are reported in this data set. Hence the data set reported here contains: f_para, f_perp, f_anti, f_omni (for each of 13 values of E), and the 13 values of V (constant, included for reference).

Acknowledgement
Please acknowledge the Wind/SWE electron instrument team and NASA/GSFC.
Contacts
RolePerson
1.PrincipalInvestigatorspase://SMWG/Person/Keith.W.Ogilvie
InformationURL
Name
Wind/SWE Description
URL
https://wind.nasa.gov/swe/index.html
Description

Wind/SWE (Solar Wind Experiment) electron instruments, history and data products

PriorIDs
spase://VHO/NumericalData/Wind/SWE/M0_PT12S
spase://VSPO/NumericalData/Wind/SWE/M0/PT12S
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb
Availability
Online
AccessRights
Open
AccessURL
Name
FTPS from SPDF (not with most browsers)
URL
ftps://spdf.gsfc.nasa.gov/pub/data/wind/swe/swe_m0/
Description

Repository of the Wind/SWE M0 (v01) electron data.

AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/wind/swe/swe_m0/
Description

In CDF via HTTP from SPDF

AccessURL
Name
CDAWeb
URL
https://cdaweb.sci.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=WI_M0_SWE&index=sp_phys
ProductKey
WI_M0_SWE
Format
CDF
Acknowledgement
Please acknowledge the CDAWeb team and NASA/GSFC's NSSDC.
ProviderResourceName
WI_M0_SWE
ProviderVersion
v01
InstrumentIDs
spase://SMWG/Instrument/Wind/SWE
MeasurementType
ThermalPlasma
TemporalDescription
TimeSpan
StartDate
2002-08-16 00:00:00Z
RelativeStopDate
-P2M
Note
Time span ranges from instrument reconfiguration up to present.
Cadence
PT12S
Exposure
PT09S
ObservedRegion
Heliosphere.NearEarth
ObservedRegion
Heliosphere.Inner
ObservedRegion
Earth.Magnetosheath
ObservedRegion
Earth.Magnetosphere.Magnetotail
Keywords
Solar Wind Plasma
Parameter #1
Name
Time
ParameterKey
Epoch
Description

Timestamp marks beginning of a measurement interval.

Caveats
Measurements are from observations over three spin periods, totaling approx 9 sec, but read out about every 12-15 sec, depending on real-time telemetery throughput.
Units
CDF_Epoch
ValidMin
01-Jan-1990 00:00:00.000
ValidMax
31-Dec-2029 23:59:59.999
FillValue
31-Dec-9999 23:59:59.999
Support
SupportQuantity
Temporal
Parameter #2
Name
Electron Speed
ParameterKey
Ve
Description

Electron speed corresponding to fluxes, by channel (constant, included for reference).

Units
cm/s
UnitsConversion
1e-2>m/s
RenderingHints
DisplayType
StackPlot
AxisLabel
Ve
ValueFormat
E12.5
ScaleType
LinearScale
Structure
Size
13
Description

For energy channel EXX, Ve[XX] gives the corresponding electron speed (cm/s).

ValidMin
0.0
ValidMax
1.0E10
FillValue
-1.0E31
Particle
ParticleType
Electron
Qualifier
Magnitude
ParticleQuantity
Velocity
Parameter #3
Name
Electron flux, parallel average
ParameterKey
f_para
Description

Electron flux, parallel average, by channel. For each flux value, f_para[i], Ve[i] gives the corresponding electron speed (cm/s).

Units
#/[cc*(cm/s)^3*str]
RenderingHints
DisplayType
StackPlot
AxisLabel
f_para
ValueFormat
E12.5
ScaleType
LogScale
Structure
Size
13
Description

For energy channel EXX, f_para[XX] gives the contents (for fluxes with directions roughly parallel to B) of energy-bin XX=: 00, 01, ..., 12.

ValidMin
1.0E-33
ValidMax
1.0E-23
FillValue
-1.0E31
Particle
ParticleType
Electron
Qualifier
Vector
Qualifier
Average
ParticleQuantity
PhaseSpaceDensity
Parameter #4
Name
Electron flux, perpendicular average
ParameterKey
f_perp
Description

Electron flux, perpendicular average, by channel. For each flux value, f_perp[i], Ve[i] gives the corresponding electron speed (cm/s).

Units
#/[cc*(cm/s)^3*str]
RenderingHints
DisplayType
StackPlot
AxisLabel
f_perp
ValueFormat
E12.5
ScaleType
LogScale
Structure
Size
13
Description

For energy channel EXX, f_perp[XX] gives the contents (for fluxes with directions roughly perpendicular to B) of energy-bin XX=: 00, 01, ..., 12.

ValidMin
1.0E-33
ValidMax
1.0E-23
FillValue
-1.0E31
Particle
ParticleType
Electron
Qualifier
Vector
Qualifier
Average
ParticleQuantity
PhaseSpaceDensity
Parameter #5
Name
Electron flux, anti-parallel average
ParameterKey
f_anti
Description

Electron flux, anti-parallel average, by channel. For each flux value, f_anti[i], Ve[i] gives the corresponding electron speed (cm/s).

Units
#/[cc*(cm/s)^3*str]
RenderingHints
DisplayType
StackPlot
AxisLabel
f_anti
ValueFormat
E12.5
ScaleType
LogScale
Structure
Size
13
Description

For energy channel EXX, f_anti[XX] gives the contents (for fluxes with directions roughly anti-parallel to B) of energy-bin XX=: 00, 01, ..., 12.

ValidMin
1.0E-33
ValidMax
1.0E-23
FillValue
-1.0E31
Particle
ParticleType
Electron
Qualifier
Vector
Qualifier
Average
ParticleQuantity
PhaseSpaceDensity
Parameter #6
Name
Electron flux, omni-directional average
ParameterKey
f_omni
Description

Electron flux, omni-directional average, by channel. For each flux value, f_omni[i], Ve[i] gives the corresponding electron speed (cm/s).

Units
#/[cc*(cm/s)^3*str]
RenderingHints
DisplayType
StackPlot
AxisLabel
f_omni
ValueFormat
E12.5
ScaleType
LogScale
Structure
Size
13
Description

For energy channel EXX, f_omni[XX] gives the contents (for fluxes with any directions relative to B) of energy-bin XX=: 00, 01, ..., 12.

ValidMin
1.0E-33
ValidMax
1.0E-23
FillValue
-1.0E31
Particle
ParticleType
Electron
Qualifier
Vector
Qualifier
Average
ParticleQuantity
PhaseSpaceDensity