ID identification

limited feature extraction / anomaly detection

There are couple of ways to identify the ID.

• Variance method (liuMagneticDiscontinuitiesSolar2022?) : Large variance in the magnetic field compared with neighboring intervals (see notebook)

• Partial variance increment (PVI) method :

  • (vaskoKineticscaleCurrentSheets2022?)

• B-criterion (burlagaTangentialDiscontinuitiesSolar1969?) : a directional change of the magnetic field larger than 30° during 60 s

• TS-criterion (Tsurutani and Smith 1979) : \(|ΔB|/|B| \geq 0.5\) within 3 minutes (see notebook)

Traditional methods (B-criterion and TS-criterion) rely on magnetic field variations with a certain time lag. B-criterion has, as its main condition. In their methods, the IDs below the thresholds are artificially abandoned. Therefore, identification criteria may affect the statistical results, and there is likely to be a discrepancy between the findings via B-criterion and TS-criterion.

References

Tsurutani, Bruce T., and Edward J. Smith. 1979. “Interplanetary Discontinuities: Temporal Variations and the Radial Gradient from 1 to 8.5 AU.” Journal of Geophysical Research: Space Physics 84 (A6): 2773–87. https://doi.org/10.1029/JA084iA06p02773.