QSAS Index CVA-CTA-Calculator

Contents:

Overview

This PlugIn calculates a boundary norma and boundary normal velocity according to the CTA (Constant Thickness Approach) and CVA (Constant Velocity Approach) methods listed in Haaland et al, Annales Geophysicae, No 2, 2004.



Input data

Required inputs are the four spacecraft positions, the center time and the relative crossing times for the four spacecrafts. An optional array with crossing half durations may suypplied - CTA outputs (normal, velocity and thickness) are then returned.



Outputs

Output quantities are:

- CVA_Normal - vector with the boundary unit normal from CVA
- CTA_Normal - vector with the boundary unit normal from CTA (if half thicknesses supplied)
- Vn_Cva - boundary velocity along the CTA_normal

In addition, the normals and velocities (and CTA thickness) is printed to the standard output window.



Bugs/Caveats

Important: Note that the crossing durations are characteristic half time thicknesses; i.i., the time [in seconds] it takes for a SC to transverse from the outher edge of the boundary to the centre of the boundary.



Other MPE/ISSI PlugIns



SEH, 13 Jan, 2004