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**
**  BOOTSTRAP CURRENT CALCULATION FOR NONTHERMAL DISTRIBUTIONS	
**
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**
**
**  bootcalc="disabled" (default) 
**          ="method1" or "method2", then compute jump conditions
**           at the trapped-passing boundary, simulating finite
**           banana width effects.  This gives a numerical 
**           calculation of bootstrap current. (Doesn't work if
**           implct.ne."enabled".or.lrz.eq.1)
**           "method1" uses radial expansion of local distribution
**             function (f=f_o-u_par/omega_c_pol*d(f)/dr)).
**           "method2" connects co-(counter-)passing region to trapped
**             particle distr. displaced half banana width
**             inwards (outwards).  (Presently assumes positive plasma
**             current.  9/93.  Needs more checking out, BH 990928)
**           See R.W.Harvey and G.Taylor, Electron Bernstein wave-bootstrap
**           current synergy in the National Spherical Torus Experiment", 
**           Physics of Plasmasa 12, 052509 (2005)
**           Only use lrzdiff.eq."disabled" with this option.
**           [YuP: Just to be clear, "method1" or "method2" produce 
**            a change in distribution function, so that the bootstrap
**            current is 'naturally' added into computation of curr() array
**            through this modification of the distribution function;
**            See functions bsl() and bsu() for details.
**            This is different from bootst="enabled" option, see below,
**            which does not produce a change in distribution function,
**            but only evaluates the bs current for general and Maxwellian
**            species based on analytical formulas; 
**            see subr.tdboothi for details, also arrays bscurm(lrz,ksp,ktype).
**            These bscurm arrays are saved into mnemonic.nc,
**            and also plotted in *.ps file (see subr.tdpltmne). 
**  bootupdt="disabled" (default)
**          ="enabled" update f_o in bootstrap calculations beyond
**             initial set-up of the distribution at nonboot.
**  bootsign=+1.0 (default)
**          =a multiplier in bootstrap current calculation of the
**           jump in the distribution at trapped-passing boundary.
**           Positive bootsign gives contibution in the positive plasma
**           current direction for the usual negative radial 
**           plasma derivatives. (The direction of the plasma
**           current is derived from the eqdsk plasma current.
**           Positive is counter-clockwise viewed from above.)
**           (As of 990901, BH).
**  nonboot= time step n at which bootstrap calculation begins
**             (default=1, not 0, since method is explicit in time).
**
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