;Name: CIRTOY
;
;+
;
;Name: CIRTOYPRAMS
;
;Purpose: To create structure containing information about a CIR density model;
; To be called by driver routine and resulting structure will be named 
; ModPramsStruct (with ModPramsStruct.name='cirtoy')
;
; Called by FOR_MODELDEFAULTS
;
;Keyword Inputs:
;
; PHYSICAL PROPERTIES
;
;
;  ALFA: 
;       controls longitudinal width
;       default, 40 (units?)
;
;  BTA:
;       controls latitudinal width
;       default, 2 (units?)
;
;  N_0:
;       controls density of CIR - multiplier on background
;
;  WWIDTH:
;       Gaussian width of CIR
;       default, 20 (units?)
;  
; HYDRO, DENSPROF, T0:
;  FORCES
;             HYDRO=5; simpler version of HYDRO=2, with only one radial power law (for far field)
;             HYDRO > 5 --> HYDRO=3
;
; KEYWORDS SET IN FOR_HYDRODEFAULTS
;
;  CDENSPROF,ODENSPROF -
;       HYDRO=0, CDENSPROF,ODENSPROF not used, set to 'NULL' and won't show up in widget
;       HYDRO=1, CDENSPROF, ODENSPROF represent density at coronal base in CGS units,
;               CDENSPROF scaled by 1d9
;               ODENSPROF scaled by 1d8
;       HYDRO=2, CDENSPROF, ODENSPROF can be input array [A,B,C,D,E,F] (units in cgs)
;               or multipliers of array [densprof*A,B,densprof*C,D,densprof*E,F]
;                     (note for widget it has to be multiplier, so, scalar)
;               closed field array defaults to values of Gibson et al 1999 WSM streamer
;               open field array defaults to values of Guhathakurta et al 1999 WSM c. hole
;               dens = A*r^-B + C*r^-D + E*r^-F
;       HYDRO=3, CDENSPROF,ODENSPROF can be array [A1,A2,A3,A4,A5,aa,bb,alpha,beta]
;              or multipliers of A1
;              closed field array defaults to Vasquez/Sittler-Guhathakurta streamer values
;              open field array defaults to Vasquez/Sittler-Guhathakurta polar
;              dens=A1*exp(A2/r)*r^-2*(1+A3/r+A4/r^2+A5/r^3)
;       HYDRO=4,ODENSPROF can be array [da,db,dc,dd,de,ta,tb,tc,td]
;              or multipliers of da
;              open field array defaults to Cranmer coronal hole values
;              dens_he= da*1e5*(db*(1./r)^dc + dd*(1./r)^de)
;               (for HYDRO=4 CDENSPROF set to 'NULL' and for_hydrodefaults will
;                          be called twice, the second time with HYDRO=3)
;       HYDRO=5, ODENSPROF CDENSPROF are density at coronal base
;              density=densprof*1d7r^T0
;
;        DEFAULT CDENSPROF=1 (CDENSPROF=6 for HYDRO=5)
;        DEFAULT ODENSPROF=1
;
;  CT0, OTO
;      HYDRO=0,1, isothermal temperature parameter value
;      HYDRO=2 -- not used set to null and not shown in widget
;               (temperature follows from density profile, ideal gas law, hydrostatic pressure balance)
;      HYDRO=3 scaling factor for model, divided by 1.5d6, and uses parameters in DENSPROF
;              temp=T0*(8e5/1.5e6)*(aa+1)/(aa+bb*r^alpha + (1-bb)*r^-beta)
;               (normalized to 1.5e6 so same T0 default can be used as other HYDRO choices)
;      HYDRO=4 scaling factor for model, divided by 1.5d6, and uses parameters in DENSPROF
;              temp_he= T0*(1e6/1.5e6)*(ta*r^tb + tc*r^td)^(-1)
;               (normalized to 1.5e6 so same T0 default can be used as other HYDRO choices)
;                       (for HYDRO=4 CTO set to 'NULL'and for_hydrodefaults will
;                          be called twice, the second time with HYDRO=3)
;        DEFAULT CTO 1.5D6
;        DEFAULT OTO 1.D6
;               (except for HYDRO=3 -- DEFAULT OTO 1.5D6)
;      HYDRO=5 -- defines slope of radial falloff; designed for far field falloff
;               (temperature follows from density profile, ideal gas law, hydrostatic pressure balance)
;        DEFAULT CTO =-4 OTO=-2