------ DD OBJECTS ------
MINIMUM VARIANCE ANALYSIS OF MAGNETIC FIELD
MINVAR OBJECT
Magnetic field data, obtained by any magnetometer onboard
INTERBALL/TAIL satellite was processed by A. Petrukovitch, N. Ryb'eva,
A. Scalsky, S. Romanov (IKI RAN) and B. Nikutowski.
Minimum variance analysis of magnetic field is useful tool in determining
the normal to the discontinuities such as magnetopause.
The TRIQL and TRIRED routines from standard IDL library are used
for eigenvalues and eigenvectors calculations. Eigenvalues correspond
to the dispersion of magnetic field along direction of minimum,
intermediate and maximum fluctuations. Eigenvectors define these directions
namely ( n, m , l) in GSM frame.
Object's output is 2 hodographs - magnetic field in the new ( n, m , l
) frame
of reference .
-
MINVAR - Hodographs Bl=f(Bn) and Bl=f(Bm). Eigenvalues
and eigenvectors in GSM frame are output.
NOTE:
-
MINVAR is called with parameter defining magnetometer (0 - FM3,
1 - MIF)
-
Xrange (nT) and Yrange (nT) should be specified.
-
Attitude data is necessary.
Example
request file:
001
minvar 0.05 0.4 .95 .65 -50. 50. -50. 50 1
1996:114:23:22:00
000:00:02:00
Output:
