INTRODUCTION:

The T(ransformed) data files for the Cluster EFW instrument contain 
spin-period E-Field, SC potential and position data from spacecraft #4.
The E-field data is corrected for vxB.

  The data are stored in .cdf files, which may be downloaded or displayed 
and manipulated using provided IDL routines.  Summary plots for quick 
viewing are also provided.  The data are provided by date, YYMMDD, in 24
hour increments for most of the storms of interest.

  The T(ransformed) data are located in the "T_data" directory with summary 
plots in the "T_plots" directory.


COORDINATE SYSTEMS:

  The E-field data are given as GSE X & Y coordinates since the spin-axes of the
spacecraft are nearly aligned with GSE-Z and Cluster E-field is only measured
in the spin plane.  The exact spin axis for each day is provided in a text
file in both the data and plot directories.


IDL CODE:

  To use the provided IDL code to view/manipulate the data, first  
change to the polar_efi directory, then type the following line at
the Unix prompt as written:

    setenv IDL_PATH "<IDL_DEFAULT>:+."

  You may then run IDL.

  The program for viewing/loading the data is:
    cdaw_efw_t_read.pro
  (The header of the program gives a full description)

  The program reads the data in from the appropriate
data directory and stores them in "tplot", for those familiar with that
routine.  The data may also be returned as arrays from the programs.
If returned as arrays, the array is a 2-d array with [*,0] the Unix 
times of the data and [*,X] the data quanties.  There is also a 
string label array returned which gives the data quantity descriptions
and units in the order the quantities are in the data array.

  If using "tplot" to display the data, simply execute:

    print,cdaw_efw_t_read(011106)

for example, and use normal "tplot" routines.

  If loading the data arrays, execute:

    print,cdaw_efw_t_read(011106,data=data,dat_lbl=dtlb,position=pos,$
      pos_lbl=pslb,spin_ax_gse=spinax)

for example.

  The program returns: 1=success, 0=failure


03/13/05
--
John Dombeck
Space Plasma Physics Group
University of Minnesota