Data Access
MAGNETIC CLOUD FIT PARAMETERS AS DETERMINED BY MFI DATA. The table consists of estimated start and end times, as designated, and physical quantities that were estimated by a magnetic field model [Lepping et al., 1990] that assumes that the field within a magnetic cloud is force free, i.e., so that the electrical current and the magnetic field are aligned and proportional in strength everywhere within its volume. The angles φA and θA refer to the estimated direction of the cloud's axis, where φA is a longitude and θA is a latitude in GSE coordinates. 2Ro is the diameter (in AU) of the magnetic cloud, assumed circular in cross-section, based on model results and the radial speed of the solar wind provided by the WIND SWE instrument (K. W. Ogilvie, PI). Bo is the model-estimated magnetic field strength for the axis of the cloud. We point out that the spacecraft rarely encounters the actual axis, but passes above or below at various closest approach (CA) distances that are also estimated by the model (not shown explicitly here - but see CA% below.) χR is actually chi/√(3N-5), based on the reduced chi-squared value, which is the usual chi-squared value divided by (3N-n), where N is the number of points (usually hour averages) used in the model fitting and n is fixed at 5 which is the number of parameters fitted up to this time; two other parameters are fitted later in the process, making it a 7 parameter model. H represents helical field handedness, right-or-left-handed. CA% means the ratio of CA distance of the spacecraft from the cloud's axis to the cloud's radius, expressed in percentage. Φ is the estimated magnetic flux along the axis of the magnetic cloud where Φ= 1.36 BR**2.
Version:2.6.0
MAGNETIC CLOUD FIT PARAMETERS AS DETERMINED BY MFI DATA. The table consists of estimated start and end times, as designated, and physical quantities that were estimated by a magnetic field model [Lepping et al., 1990] that assumes that the field within a magnetic cloud is force free, i.e., so that the electrical current and the magnetic field are aligned and proportional in strength everywhere within its volume. The angles φA and θA refer to the estimated direction of the cloud's axis, where φA is a longitude and θA is a latitude in GSE coordinates. 2Ro is the diameter (in AU) of the magnetic cloud, assumed circular in cross-section, based on model results and the radial speed of the solar wind provided by the WIND SWE instrument (K. W. Ogilvie, PI). Bo is the model-estimated magnetic field strength for the axis of the cloud. We point out that the spacecraft rarely encounters the actual axis, but passes above or below at various closest approach (CA) distances that are also estimated by the model (not shown explicitly here - but see CA% below.) χR is actually chi/√(3N-5), based on the reduced chi-squared value, which is the usual chi-squared value divided by (3N-n), where N is the number of points (usually hour averages) used in the model fitting and n is fixed at 5 which is the number of parameters fitted up to this time; two other parameters are fitted later in the process, making it a 7 parameter model. H represents helical field handedness, right-or-left-handed. CA% means the ratio of CA distance of the spacecraft from the cloud's axis to the cloud's radius, expressed in percentage. Φ is the estimated magnetic flux along the axis of the magnetic cloud where Φ= 1.36 BR**2.
| Role | Person | StartDate | StopDate | Note | |
|---|---|---|---|---|---|
| 1. | Author | spase://SMWG/Person/Ronald.P.Lepping | |||
| 2. | MetadataContact | spase://SMWG/Person/Olga.Y.Uritskaya |
Event identification number
Year
START TIME, month
START TIME, day
START TIME, day of the year
START TIME, hour
END TIME, month
END TIME, day
END TIME, day of the year
END TIME, hour
Duration of the encounter
Axis direction in terms of (GSE) estimated longitude (φA) and latitude (θA)
Axis direction in terms of (GSE) estimated longitude (φA) and latitude (θA)
An average solar wind speed
Estimated diameter (in AU), where Ro is the model estimated radius
Estimated axial field magnitude (in nT)
Handedness (+1 for right-handed or -1 for left-handed)
χR, square root of reduced chi-squared of fit
Asymmetry factor (%)
CA(%), estimated relative closest approach distance, Yo/Ro (%). Case marked with * are possible core-annulus cases and are not necessarily expected to have a small "check" - see ck%
Axial magnetic flux (in 1020 Mx)
Axial current density (in μA/km2)
Analysis interval length (averages of 15 minutes, 30 minutes, or 1 hour)
Cone angle, the angle between the MC's axis and the X-axis (GSE)
"Check" of estimated radius by using duration, speed and βCA
Total axial current (in 10^8A)
Number of "points" (averages-see footnote I) used in the fitting interval
The vector (<BX>CI,<BY>CI,<BZ>CI), where CI refers to Cloud coordinates
The vector (<BX>CI,<BY>CI,<BZ>CI), where CI refers to Cloud coordinates
The vector (<BX>CI,<BY>CI,<BZ>CI), where CI refers to Cloud coordinates
The flag (f) to denote ability to determine handedness (H)
The flag (F) to denote ability to determine convergence
Qo, estimated Quality of the model fitting: Qo = 1, 2 and 3 for good, fair and poor, respectively.
For definition see https://wind.nasa.gov/mfi/appendix.html