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IMP 8 bow shock crossings

ResourceID
spase://NASA/Catalog/BS_IMP8

Description

A complete list of bow shock crossings observed by IMP 8 spacecraft. The shock crossings were manually identified in magnetic field and/or thermal plasma measurements by J. Merka, A. Szabo, K. Paularena, J. Richardson, and T. Narock.
Each identified crossing was reviewed by at least two persons from the team.

  Upstream parameters are as measured by IMP 8 on the solar wind side of the shock, typically over a few-minute interval judged by the IMP field and plasma teams as stable. For multiple-shock records, all upstream parameters are for the first shock crossing.
 
  Downstream parameters are as measured by IMP 8 on the magnetosheath side of the shock, typically over a few-minute interval. For a multiple-shock records, all downstream parameters are for the first shock crossing if possible.

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Details

Version:2.3.0

Catalog

ResourceID
spase://NASA/Catalog/BS_IMP8
ResourceHeader
ResourceName
IMP 8 bow shock crossings
ReleaseDate
2020-07-07 19:17:05Z
Description

A complete list of bow shock crossings observed by IMP 8 spacecraft. The shock crossings were manually identified in magnetic field and/or thermal plasma measurements by J. Merka, A. Szabo, K. Paularena, J. Richardson, and T. Narock.
Each identified crossing was reviewed by at least two persons from the team.

  Upstream parameters are as measured by IMP 8 on the solar wind side of the shock, typically over a few-minute interval judged by the IMP field and plasma teams as stable. For multiple-shock records, all upstream parameters are for the first shock crossing.
 
  Downstream parameters are as measured by IMP 8 on the magnetosheath side of the shock, typically over a few-minute interval. For a multiple-shock records, all downstream parameters are for the first shock crossing if possible.
Contacts
RolePerson
1.DataProducerspase://SMWG/Person/Jan.Merka
PriorIDs
spase://VMO/Catalog/BS_IMP8
spase://VSPO/Catalog/BS_IMP8
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/VHO-VMO
Availability
Online
AccessRights
Open
AccessURL
Name
Download of IMP 8 bow shock crossing list
URL
https://vho.nasa.gov/mission/imp8/bowshocks/
Description

Repository of IMP 8 bow shock crossings

Format
Text
Encoding
ASCII
InstrumentIDs
spase://SMWG/Instrument/IMP8/MAG
spase://SMWG/Instrument/IMP8/PLS
PhenomenonType
BowShockCrossing
TimeSpan
StartDate
1973-10-31 07:31:00Z
StopDate
2000-06-08 16:45:00Z
Caveats
The times are estimated to a minute (truncated).
Parameter #1
Name
Time
ParameterKey
Fields 1-4
Description

Time of the bow shock crossing. In general, the minute given is that in/during which the crossing is observed. For "extended" crossings, the minute given is that in which the peak of the shock overshoot occurs. For records recording multiple shock crossings, the minute is the minute of the first shock crossing.

Caveats
Truncated to a minute precision.
Structure
Size
4
Element
Name
Year
Index
1
ParameterKey
Field 1
Element
Name
Day of year
Index
2
ParameterKey
Field 2
Element
Name
Hour
Index
3
ParameterKey
Field 3
Element
Name
Minute
Index
4
ParameterKey
Field 4
Support
SupportQuantity
Temporal
Parameter #2
Name
Orbit number
ParameterKey
Field 5
Description

Orbit number per IMP project

Support
SupportQuantity
Other
Parameter #3
Name
Orbit leg
ParameterKey
Field 6
Description

0 for solarwindward orbit leg, 1 for magnetotailward orbit letg

Support
SupportQuantity
Other
Parameter #4
Name
Sequence number
ParameterKey
Field 7
Description

Sequence number of the crossing for this orbit leg (1, 2, ...N; N will be an odd number except for Transdr=2 cases). For multiple-shock records (Flag2 = 6 or 7), this number increments by one for unresolvable shock periods (Flag2=6) or by the number of resolvable shocks plus the number of unresolvable-shock subintervals.

Support
SupportQuantity
Other
Parameter #5
Name
Transdr
ParameterKey
Field 8
Description

Direction of crossing transition: 0 - spacecraft passing into solar wind, 1 - spacecraft passing into magnetosheath, 2 - non-resolvable shock(s), same domain (solar wind or magnetosheath) on both sides. See Timespan for duration of the crossing.

Support
SupportQuantity
Other
Parameter #6
Name
Flag1
ParameterKey
Field 9
Description

Observation flag. Flag1 has the following values:
1. Shock observed in field and plasma data
2. Field data missing
3. Plasma data missing
4. Inferred crossing, data gap
5. Inferred crossing, data but no likely shock visible.
When a bow shock crossing is inferred to have happened during some time interval, the start time of the interval is given in the record. In addition, if the interval is less than 30 minutes in duration, the location of IMP 8 at the start of the interval is also given in the record. Otherwise the IMP location words have fill values in them. Note that the Timespan parameter is used to give the interval duration in such cases. In general, upstream parameter values are given as fill values for such cases. These intervals typically correspond to data gaps (Flag 1 = 4) with IMP 8 clearly in the solar wind on one side of the gap and in the magnetosheath on the other side. There are rare Flag 1 = 5 cases where IMP 8 is clearly in the solar wind on one side of the interval and in the magnetosheath on the other side and wherein there are data within the interval, yet it is impossible to discern on a finer scale when IMP 8 passed between the solar wind and the magnetosheath.

Support
SupportQuantity
Other
Parameter #7
Name
Flag2
ParameterKey
Field 10
Description

Shock cleanliness flag. Flag 2 has the following values.
(Note in particular that values 1-4 are relevant to cases of one shock while 6-8 are relevant to cases of multiple close shocks; note also that some or all of the members of a set of multiple close shocks may be unresolvable from each other and, separately, may be ambiguous in the sense of values 2-4 for individual shocks. In general, where an interval of multiple close shocks ends with a clean shock, there will be a separate record for that shock.)
1. The shock is clean and unambiguous in all available data
2. The shock is clean in field, ambiguous in plasma data
3. The shock is clean in plasma, ambiguous in field data
4. The shock is ambiguous in all available data
5. Used for inferred crossings (Flag1 = 4 or 5)
6. Multiple unresolvable shocks possibly involving relatively clean shocks at the start and end (Sequence number increments by 1 whether same domain or different domains on two sides)
7. Multiple resolvable shocks with no subinterval(s) of unresolvable shocks. Used on for intervals with no shock pair separated by >15 minutes. Sequence number increments by sum of number of shocks in the interval or one less if the ending shock is also given a separate record of its own.
8. Multiple shocks, mixed resolvable/unresolvable, some resolvable shocks may be ambiguous. Sequence number increments by the number of resolvable shocks in the interval or one less if the ending shock is given a record of its own.

Support
SupportQuantity
Other
Parameter #8
Name
Flag3
ParameterKey
Field 11
Description

Upstream cleanliness flag. Flag 3 has the following values:
1. Upstream values steady and well defined
2. Upstream values unsteady and uncertainly defined
3. Used for inferred crossings (Flag1 = 4)

Support
SupportQuantity
Other
Parameter #9
Name
Spacecraft position in GSE
ParameterKey
Field 12-14
Description

Spacecraft positition in GSE.

Units
Re
UnitsConversion
6.378e6>m
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
Xgse
Qualifier
Component.I
Index
1
ParameterKey
Field 12
Element
Name
Ygse
Qualifier
Component.J
Index
2
ParameterKey
Field 13
Element
Name
Zgse
Qualifier
Component.K
Index
3
ParameterKey
Field 14
FillValue
999.9
Support
SupportQuantity
Positional
Parameter #10
Name
Spacecraft position in GSM
ParameterKey
Field 15-16
Description

Spacecraft positition in GSM (components Y and Z only).

Units
Re
UnitsConversion
6.378e6>m
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
2
Element
Name
Ygsm
Qualifier
Component.J
Index
1
ParameterKey
Field 15
Element
Name
Zgsm
Qualifier
Component.K
Index
2
ParameterKey
Field 16
FillValue
999.9
Support
SupportQuantity
Positional
Parameter #11
Name
B GSE
ParameterKey
Field 17-19
Description

Upstream magnetic field components in GSE

Units
nT
UnitsConversion
1e-9>T
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
Bx GSE
Qualifier
Component.I
Index
1
ParameterKey
Field 17
Element
Name
By GSE
Qualifier
Component.J
Index
2
ParameterKey
Field 18
Element
Name
Bz GSE
Qualifier
Component.K
Index
3
ParameterKey
Field 19
FillValue
999.9
Field
Qualifier
Vector
Qualifier
Average
FieldQuantity
Magnetic
Parameter #12
Name
B GSM
ParameterKey
Field 20-21
Description

Upstream magnetic field components Y and Z in GSM

Units
nT
UnitsConversion
1e-9>T
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
2
Element
Name
By GSE
Qualifier
Component.J
Index
1
ParameterKey
Field 20
Element
Name
Bz GSE
Qualifier
Component.K
Index
2
ParameterKey
Field 21
FillValue
999.9
Field
Qualifier
Component.J
Qualifier
Component.K
Qualifier
Average
FieldQuantity
Magnetic
Parameter #13
Name
V GSE
ParameterKey
Field 22-24
Description

Solar wind velocity upstream of the shock.

Caveats
The components of the velocity vector are negative, i.e. the vector is anti-aligned with the measured velocity vector.
Units
km/s
UnitsConversion
1e3>ms/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
-Vx GSE
Qualifier
Component.I
Index
1
ParameterKey
Field 22
Element
Name
-Vy GSE
Qualifier
Component.J
Index
2
ParameterKey
Field 23
Element
Name
-Vz GSE
Qualifier
Component.K
Index
3
ParameterKey
Field 24
FillValue
9999.9
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
Velocity
Parameter #14
Name
Nu
ParameterKey
Field 25
Description

Upstream solar wind proton density

Units
cm^-3
UnitsConversion
1e3>m^-3
FillValue
999.9
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
NumberDensity
Parameter #15
Name
Nd
ParameterKey
Field 26
Description

Downstream (magnetosheath) proton density

Units
cm^-3
UnitsConversion
1e3>m^-3
FillValue
999.9
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
NumberDensity
Parameter #16
Name
T
ParameterKey
Field 27
Description

Upstream proton temperature

Units
K
FillValue
9999999
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
Temperature
Parameter #17
Name
Time span
ParameterKey
Field 28
Description

The time span gives duration, in minutes, of gaps for inferred crossings (flag 1 = 4 cases) or duration of periods of multiple unresolved or resolved shocks (flag 2 = 6 or 7 cases). For other cases, the time span gives the shock duration. In the majority of cases wherein the shock occurs in a fraction of minute, this field has value 0.

Units
minutes
UnitsConversion
60>s
FillValue
9999
Support
SupportQuantity
Temporal
Parameter #18
Name
Btot
ParameterKey
Field 29
Description

Upstream magnetic field intensity calculated from magnetic field components.

Units
nT
UnitsConversion
1e-9>T
FillValue
999.9
Field
Qualifier
Magnitude
Qualifier
Average
FieldQuantity
Magnetic
Parameter #19
Name
Vtot
ParameterKey
Field 30
Description

Upstream solar wind proton flow speed

Units
km/s
UnitsConversion
1e3>m/s
FillValue
9999.9
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
FlowSpeed
Parameter #20
Name
Vs
ParameterKey
Field 31
Description

Upstream sound speed

Units
km/s
UnitsConversion
1e3>m/s
FillValue
9999.9
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
SoundSpeed
Parameter #21
Name
Va
ParameterKey
Field 32
Description

Upstream Alfven speed

Units
km/s
UnitsConversion
1e3>m/s
FillValue
9999.9
Support
Qualifier
Average
SupportQuantity
Other
Parameter #22
Name
Vms
ParameterKey
Field 33
Description

Upstream magnetosonic speed

Units
km/s
UnitsConversion
1e3>m/s
FillValue
9999.9
Support
Qualifier
Average
SupportQuantity
Other
Parameter #23
Name
Ms
ParameterKey
Field 34
Description

Upstream sonic Mach number

FillValue
99.9
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
SonicMachNumber
Parameter #24
Name
Ma
ParameterKey
Field 34
Description

Upstream Alfven Mach number

FillValue
999.9
Support
Qualifier
Average
SupportQuantity
Other
Parameter #25
Name
Mms
ParameterKey
Field 35
Description

Upstream magnetosonic Mach number

FillValue
99.9
Support
Qualifier
Average
SupportQuantity
Other
Parameter #26
Name
Beta
ParameterKey
Field 36
Description

Upstream plasma beta

FillValue
-999.99
Support
Qualifier
Average
SupportQuantity
Other
Parameter #27
Name
Psw
ParameterKey
Field 37
Description

Upstream solar wind flow pressure

Units
nPa
UnitsConversion
1e-9>Pa
FillValue
99.99
Particle
ParticleType
Proton
Qualifier
Average
ParticleQuantity
Pressure
Parameter #28
Name
Str
ParameterKey
Field 38
Description

Shock strength: downstream to upstream density ratio (Nd/Nu).

FillValue
9.9
Support
SupportQuantity
Other
Parameter #29
Name
IMF cone
ParameterKey
Field 39
Description

IMF cone angle = acos(|Bx|/Bt)

Units
deg
CoordinateSystem
CoordinateRepresentation
Spherical
CoordinateSystemName
GSM
FillValue
999
Field
Qualifier
DirectionAngle
Qualifier
Average
FieldQuantity
Magnetic
Parameter #30
Name
IMF clock
ParameterKey
Field 40
Description

IMF clock angle = atan(|By GSM|/Bz GSM)

Units
deg
CoordinateSystem
CoordinateRepresentation
Spherical
CoordinateSystemName
GSM
FillValue
999
Field
Qualifier
DirectionAngle
Qualifier
Average
FieldQuantity
Magnetic