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Last modified: Mon May 5 18:17:35 2025.
PROCEDURE:
lingradest
PURPOSE:
IDL subroutine to calculate magnetic field gradients, divergence, curl, and field line
curvature from 4-point observations
Input:
B-field components from the four probes
Coordinates from the four probes
Length of vectors (all variables should be interpolated to the same length)
Method used:
Linear Gradient/Curl Estimator technique
see Chanteur, ISSI, 1998, Ch. 11
Originally designed for Cluster by A. Runov (2003)
$LastChangedBy: egrimes $
$LastChangedDate: 2022-03-29 13:55:04 -0700 (Tue, 29 Mar 2022) $
$LastChangedRevision: 30732 $
$URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/projects/mms/common/curlometer/lingradest.pro $
(See projects/mms/common/curlometer/lingradest.pro)
PROCEDURE:
mms_curl
PURPOSE:
This routine calculates div B and curl B for a specified time interval
KEYWORDS:
trange: time range over which to compute the curl (will be prompted if not provided)
fields: array of tplot variables containing the B-field for each spacecraft (in GSE coordinates)
positions: array of tplot variables containing the S/C position vectors for each spacecraft (also GSE coordinates)
NOTES:
The input B-field data and position data are expected to be in
GSE coordinates
Original by Jonathan Eastwood, with changes from Tai Phan
Minor modifications for SPEDAS by egrimes
For more info on this method, see:
Chanteur, G., Spatial Interpolation for Four Spacecraft: Theory,
Chapter 14 of Analysis methods for multi-spacecraft data, G.
Paschmann and P. W. Daly (Eds.) ISSI Scientific Report SR-001.
$LastChangedBy: egrimes $
$LastChangedDate: 2017-04-24 12:09:49 -0700 (Mon, 24 Apr 2017) $
$LastChangedRevision: 23221 $
$URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/projects/mms/common/curlometer/mms_curl.pro $
(See projects/mms/common/curlometer/mms_curl.pro)
PROCEDURE:
mms_lingradest
PURPOSE:
Calculations of Grad, Curl, Curv,..., for MMS using
the Linear Gradient/Curl Estimator technique
see Chanteur, ISSI, 1998, Ch. 11
Based on Cluster routine (A. Runov, 2003)
Input: Bxyz from four points with the same time resolution
and same sampling intervals (joined time series)
Coordinates of the four points (R) with the same time
resolution and sampling as Bxyz
datArrLength := the length of B and R arrays (must be
the same for all vectors)
Output: bxbc, bybc, bzbc: B-field in the barycenter
LGBx, LGBy LGBz: B-gradient at the barycenter
LCxB, LCvB, LCzB: curl^B at the barycenter
curv_x_B, curv_y_B, curv_z_B: B-curvature at the
barycenter, RcurvB: the curvature radius
$LastChangedBy: egrimes $
$LastChangedDate: 2017-04-24 12:31:29 -0700 (Mon, 24 Apr 2017) $
$LastChangedRevision: 23222 $
$URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/projects/mms/common/curlometer/mms_lingradest.pro $
(See projects/mms/common/curlometer/mms_lingradest.pro)