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MetadataRightsList Access
HTML
ACE List of Disturbances and Transients, Shocks
ResourceID
spase://NASA/Catalog/ACE/Shocks
Description
The following list contains shocks observed by either MAG or SWEPAM. Whenever possible, the observation is confirmed by both instruments. The time is approximate and good to about 30 minutes. Whether the shock is (F)orward or (R)everse is listed. Initial comments are purely subjective, especially in so far as they are characterized the size of the shock as "small", "moderate" or "large", but characterizations will be improved as further analysis is performed.
The MAG instrument was activated the day of launch, August 25, 1997 and exited the Earth's magnetosphere later that same day. The shock list begins with observations from August 26. SWEPAM was activated on October 20, 1997. SWEPAM observations are not available for Dec. 4-22, 1997 or Feb. 20-23, 1998. Whenever data from both instruments are available, both are used to determine the identity of an apparent shock.
The process for identifying shocks has evolved over the mission lifetime. Whereas we began by identifying the shock times, we evolved into listing the bulk parameter jumps as fractional as taken by eye from data plots. Starting in 2002 we list the bulk parameters before and after the shock to better describe the discontinuity. The shock fit should be superior to the initial quantification, but some shocks are not well fit for reasons having to do with either data availability or background structure.
Note: The shock analysis results given were obtained by least-squares fitting of the incomplete Rankine-Hugoniot relations (temperature info. not used). The following parameters from the asymptotic upstream and downstream states are presented where available: shock normal, n, in RTN, and in angular format with uncertainty in degrees, (polar, long.), where the polar angle is measured from the positive R axis, and the longitudinal angle is measured from the positive T axis towards the N axis, the shock speed, V, given in the spacecraft frame and in the upstream plasma frame (in parentheses), in km/s, the downstream over upstream density ratio, r_n, the downstream over upstream magnetic field strength ratio, r_b, the angle between upstream magnetic field vector and the shock normal, Th_Bn, in degrees, and the upstream Mach number, M_A. We show both interactive solutions that are refined iteratively until the best set of upstream and downstream values are chosen as well as via automated solution that selects the upstream and downstream points by their internal consistency. Two sets of interactive solutions are shown as the data has been reprocessed and the new data generates a slightly different solution. The automated solutions use a point system to award goodness of fit that was developed for the automated space weather environment. Solutions with points above ~ 50 generally constitute good solutions of true shocks. Note that weak shocks with good solutions can still result in low point values.
Metadata Rights
CC0-1.0:
Creative Commons Zero v1.0 Universal
Note
CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions. The actual data/software may be subject to a different license.
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Details
Version:2.7.1
Catalog
ResourceID
spase://NASA/Catalog/ACE/Shocks
NamingAuthority
NASA
ResourceType
Catalog
ResourceHeader
ResourceName
ACE List of Disturbances and Transients, Shocks
ReleaseDate
2026-02-02 13:10:21Z
RevisionHistory
RevisionEvent
ReleaseDate
2025-06-22 18:51:38
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2026-02-02 13:10:21Z
Note
Added MetadataRightsList. Added ResourceType and NamingAuthority. Updated to 2.7.1. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. ZCB
Description
The following list contains shocks observed by either MAG or SWEPAM. Whenever possible, the observation is confirmed by both instruments. The time is approximate and good to about 30 minutes. Whether the shock is (F)orward or (R)everse is listed. Initial comments are purely subjective, especially in so far as they are characterized the size of the shock as "small", "moderate" or "large", but characterizations will be improved as further analysis is performed.
The MAG instrument was activated the day of launch, August 25, 1997 and exited the Earth's magnetosphere later that same day. The shock list begins with observations from August 26. SWEPAM was activated on October 20, 1997. SWEPAM observations are not available for Dec. 4-22, 1997 or Feb. 20-23, 1998. Whenever data from both instruments are available, both are used to determine the identity of an apparent shock.
The process for identifying shocks has evolved over the mission lifetime. Whereas we began by identifying the shock times, we evolved into listing the bulk parameter jumps as fractional as taken by eye from data plots. Starting in 2002 we list the bulk parameters before and after the shock to better describe the discontinuity. The shock fit should be superior to the initial quantification, but some shocks are not well fit for reasons having to do with either data availability or background structure.
Note: The shock analysis results given were obtained by least-squares fitting of the incomplete Rankine-Hugoniot relations (temperature info. not used). The following parameters from the asymptotic upstream and downstream states are presented where available: shock normal, n, in RTN, and in angular format with uncertainty in degrees, (polar, long.), where the polar angle is measured from the positive R axis, and the longitudinal angle is measured from the positive T axis towards the N axis, the shock speed, V, given in the spacecraft frame and in the upstream plasma frame (in parentheses), in km/s, the downstream over upstream density ratio, r_n, the downstream over upstream magnetic field strength ratio, r_b, the angle between upstream magnetic field vector and the shock normal, Th_Bn, in degrees, and the upstream Mach number, M_A. We show both interactive solutions that are refined iteratively until the best set of upstream and downstream values are chosen as well as via automated solution that selects the upstream and downstream points by their internal consistency. Two sets of interactive solutions are shown as the data has been reprocessed and the new data generates a slightly different solution. The automated solutions use a point system to award goodness of fit that was developed for the automated space weather environment. Solutions with points above ~ 50 generally constitute good solutions of true shocks. Note that weak shocks with good solutions can still result in low point values.
Contacts
Role
Person
StartDate
StopDate
Note
1.
GeneralContact
spase://SMWG/Person/Charles.W.Smith
2.
MetadataContact
spase://SMWG/Person/Olga.Y.Uritskaya
AccessInformation
RepositoryID
spase://SMWG/Repository/UNH
AccessURL
URL
http://www.ssg.sr.unh.edu/mag/ace/ACElists/obs_list.html#shocks
Format
HTML
InstrumentIDs
spase://SMWG/Instrument/ACE/MAG
spase://SMWG/Instrument/ACE/EPAM
PhenomenonType
InterplanetaryShock
TimeSpan
StartDate
1997-09-02 22:30:00
StopDate
2016-04-14 06:50:00
Parameter #1
Name
Date & Time
Support
SupportQuantity
Temporal
Parameter #2
Name
F/R
Description
(F)orward or (R)everse
Support
SupportQuantity
Orientation
Parameter #3
Name
Confirmation
Support
SupportQuantity
Other
Parameter #4
Name
Comments/Solutions 1
Support
SupportQuantity
Other
Parameter #5
Name
Comments/Solutions 2
Support
SupportQuantity
Other
Parameter #6
Name
Automated Solutions
Support
SupportQuantity
Other