PRO: THM_EFI_ExB, Ename, Bname, Sname=Sname, Vname=Vname, $ EdotB=EdotB, Btot=Btot PURPOSE: Calculate Poynting Flux and Flow Velocity INPUT: Eanme - REQUIRED. STRING Efield data name (tplot). Bname - REQUIRED. STRING Bfield data (tplot) Sname - OPTIONAL. Poynting Flux name (tplot) Vname - OPTIONAL. Velocity Flow name (tplot) CALLING: thm_efi_exb, Ename, Bname, Sname OUTPUT: Poynting Flux is Calculated INITIAL VERSION: REE 08-10-31 LASP, CU MODIFICATION HISTORY: 2010-02-21: Added a check of the coordinate systems of Ename and Bname. -JBT, CU/LASP.