Screamer Project  V3.3.1
Screamer Structure
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rwallmdl.f
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1  Subroutine rwall (dt,time,parms,rvar)
2 c
3 c
4 c Resistive Wall Model
5 c
6 c Written by Ken Struve, March 7, 1994.
7 c
8 c Modified 5/12/98 to add coax resistance
9 c
10 c Modified 7/27/98 to use the Stygar formula
11 c
12 c Modified 1/6/99 to use the newer Stygar formula
13 c
14 c Modified 10/6/06 to use most recent Stygar formula based on Stygar memo
15 c dated 29 Sept 2005.
16 c
17 c RBS: Modified 9/6/08 to change the varible dimension from dimension(1) to
18 c dimension(*), fixed a code warning
19 c
20 c**********************************************************************
21 c
22 c This routine estimates the resistive losses in the wall at very high
23 c current densities. It is based on a model by Knoepfl, in the book,
24 c Pulsed High Magnetic Fields, but modified by Bill Stygar. This
25 c is only an estimate at this time since it does not use the actual
26 c current profile to determine the magnetic diffusion into the conductor,
27 c but rather uses a square root of t dependence. Also, this routine does
28 c not consider current that is carried in a plasma sheath, unless that
29 c sheath is produced by vaporized conductor. The resistance R for a
30 c disk transmission line is described as
31 c
32 c R[Ohms] = sqrt(rho muo / pi^3 t) (sum(ln(router/rinner)) +
33 c sum(lcyl/rcyl))
34 c
35 c where rho is 7.2e-7 ohm-m for stainless steel, t is the time from the start
36 c of the current, diskinner and diskouter are the inner and outer
37 c radii of the disk mitls, and lcyl and rcyl are the lengths and radii
38 c of each individual coaxial section. All units are MKS. NOTE: router
39 c should only extend to the post hole convolute for Z or ZX. This formula is
40 c only valid for (B/Bo)^2 > 1, where Bo is sqrt(2 muo / beta), and beta is the
41 c resistivity heat coefficient. rho = rho(To) * (1 + beta Q), where Q = cp delta T
42 c
43 c The calculation can be simplified to
44 c
45 c R[Ohms] = 1.708e-7 / sqrt(t) * geometry factor * scaling factor
46 c
47 c The variables diskfact and cylfact have already been used to create the variable
48 c geomfact, and are therefore not used in this routine. The variable g (which does not change)
49 c allows the user to adjust the conductivity to account for temperature. The value
50 c of this constant is normally 1. For higher assumed higher temperatures it could be 2 or 3.
51 c
52 c Define passed variables
53 c
54  real dt, time, parms(*), rvar
55 c
56 c Define internal variables
57 c
58  real factor, t_in, g, diskfact, cylfact, geomfact, tau
59 c
60  parameter(factor=1.708e-7)
61 c
62  t_in = parms(1)
63  g = parms(2)
64  diskfact = parms(3)
65  cylfact = parms(4)
66  geomfact = parms(5)
67 c
68 c
69 c Calculate the resistance
70 c
71 c
72  if(time .le. t_in) then
73  rvar=0.0
74  else
75  tau = time-t_in+1.0e-10
76  rvar = factor * geomfact * g / sqrt(tau)
77  endif
78 c
79 c
80 c
81  return
82  end
83 
c *****************************************************************************c Various format statements for read_screamer_data output c To get these into made format to be characters c for each line corrected spelling errors in format added statement for Zflow Plasma Loss Model added format for CSV output type fixed more lines longer than characters added format for Measure Zflow Block and forward c reverse current directions in Zflow plasma loss c and Zflow POS models added format for SFC output type c removed from all code calls c c c c c a80 c i10 c No grids on plots c Do not write files containing the plotted points c Execute only one cycle c Do not echo the setup parameters and indicies c c &exitting c a13 c c c c c c c c102 c &described as a function of time c c c &described as a function of time c c c &function of time c c shell c &min A K c &trapped field time
Definition: zdemfmt.h:85
subroutine rwall(dt, time, parms, rvar)
Definition: rwallmdl.f:1