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CIS/CODIF Moments Calculation C CAT Extension Package. O. Marghitu CIS Meeting, Paris June 9 -1 1 , 2003 Background: Cluster, artist view (ESA image). Preamble. To Do List – CIS Meeting September Error in V - S/W implementation B-aligned reference system
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CIS/CODIF Moments CalculationCCAT Extension Package O. Marghitu CIS Meeting, Paris June9-11, 2003 Background: Cluster, artist view (ESA image)
Preamble To Do List – CIS Meeting September • Error in V - S/W implementation • B-aligned reference system • Error in P and T - S/W implementation • Finite (DE, DW) error 1, 2, and 3 included in the Extension Package Download, including documentation, available at: ftp://mpedmz1.mpe.mpg.de/pub/plasma/cis/ccat_extension.tar.gz
Outline • New options • Installation and use • Consistency checks • Updates for ccat4 • Examples • To Do
A New Options A • Choice of the reference system – keyword RFS • INS, GSE, GSM, MAG, DIA • Computation of the statistical error – keyword ERR_S • Can be used with any moment and RFS, except for DIA • Summation over several time bins – keyword SUM • The data is summed prior to any other processing • Pitch-angle selection – keywords PITCH_ANGLE and PA180 • With PA180 one switches between physical (0–180) and instrumental definitions (0 – 360) • Computation of the electric field, keyword EFIELD • Effective only in association with moment=‘V‘
B Installation and Use B • The new or modified ccat routines are collected under zccat_om, which has to be copied to $CCAT • Some of the routines depend on the ccat version – v.3 or v.4 – so that two sub-packages are needed • To start using the code check COD_3dmom_crib in zccat_om. A mandatory step is the compilation of the new package, done with @§CCAT/zccat_om/compile_extension • To switch back to the original code run @§CCAT/zccat_om/compile_original
C Consistency Checks C • The density does not depend on the reference system • The absolute values for vectors and the average value for tensors, as well as their errors, do not depend on the ref. sys. • The GSE and GSM x (vectors) and xx (tensors) components are identical • The results obtained for PITCH_ANGLE=[0 , f], PA180=1, are identical with those for [360-f , ], PA180=0 • The relative error in the density and in the diagonal elements of pressure and temperature (xx, yy, zz) is always in [0 , 1] Notes on the relative error for vectors: • Can be larger than 1, e. g. with distributions close to isotropic • Can be very small when the distribution is cold and beam-like. In such cases it is the finite (DE, DW) error which prevails
D Updates for ccat4 D In ccat4 there are 3 new keywords: • INCRATES – dead-time correction • SPILL – subtraction of the H+ spill-over • BKG – subtraction of the background (for perigee passes) The errors are computed by using: • The measured counts and an increased 1-count differential energy flux, when INCRATES is set • The difference counts, when SPILL or BKG are set
DIA vs. MAG: O+ DIA vs. MAG: H+ É Examples: Pressure E
F To Do F • The magnetic data is assumed to be available. This is usually the case, but not always • Extension of the package to CIS/HIA, implying modification of PLOT_HIA_3DMOM_FROM_CRIB • Calculation of the error associated with the finite width of the energy – angle bin => more demanding task