The files emfield*.dat have following structure:

There are 6 values per line representing
(1) z (axial) coordinate in mm
(2) r (radial coordinate in mm
(3) B_z (axial) magnetic field in Tesla
(4) B_r (radial) magmetic field in Tesla
(5) E_z (axial) electric field in kV/cm
(6) E_r (radial) electric field in kV/cm

There are following field configurations:

emfield.dat -> original abBA proposal (Nov. 2004)

em_nab_1.dat Four field configurations from 
em_nab_2.dat original LoI (July 2005)
em_nab_3.dat
em_nab_4.dat

emfield_1.dat (JD Bowman emfield)
emfield_2.dat (JS Calarco emfield no. 1 72cm)
emfield_3.dat (JS Calarco emfield no. 2 98cm)
emfield_4.dat (JD Bowman reference design)

emfield_11.dat (calculates the modified "P"-type magnetic field 
                of JD Bowman's LA-UR-04-3784 note)

em_nab_last.dat (most recent Nab B field, R Alarcon, Feb. 2006, Tosca)

The magnetic fields are calculated with TOSCA,
electric fields with SIMION3D 7.0