PITHON-II Model
!
! Rick Spielman 2019-05-28
!
Time-step 1.0e-12
Resolution-time 50.0e-12
End-time 1.0e-6
Number-prints 5
Execute-cycles all
Grids no
Echo-setup no
Max-points 5001
!
!Start circuit definition
!
! Rev 4 starts with Rev 3 and puts more detail in the transmission lines and uses the correct
! water switch and pre-pulse slab details.
!
! Rev 3 Marx switch losses and accurate water line parameters
! Includes stray capacitance in the PFL and TFMR water switches
! We will be optimizing the number of stages and sub-Marxes
! Number of stages = 44
! Number of switches = 22
! Number of sub-Marxes = 8
! Stage capacitance = 300 nF
! Vcharge = 100 kV
! Initial Marx charge = 44 * 100 kV = 4.4 MV
!
! Gas switch dimensions from drawings
!
! Total Marx Capacitance = 300 nF * 8 / 44 = 54.5 nF
!
! PFL capacitance is 28.2 nF. This is distributed in a TL that is 36.6 ns long and
!   has a constant impedance of 1.3 .
!
! Include 130 m indivudual cap ESR or 65 m per pair of caps in parallel
!   X 44 stages = 2.86  per sub-Marx or 0.3575 total
! Assume that there will be 200 nH every two stages. L = 200 nH * 22 = 4.4 H.
! The total Marx inductance (caps and switches) would be 4.4 H/8 = 550 nH
!
! The matched impedance of a sub-Marx = sqrt(L/C) = 25.4 .
! The total Marx impedance is 25.4 /8 = 3.18 
! The ESR amounts to ~ 11.2% of the matched impedance.
!
! The switch model will have 22x the length of one switch per sub Marx and then will
! have 8 arc channels (sub Marxes) in parallel.
! 
! We will use a total inductance of 630 nH for the Marx and L1. This inductance is needed to 
! get the required rise time of the voltage on the PFL. This is a very conservative approacb=h.
!
!
BRANCH
!
! Capacitor capacitance and charge voltage
!
RCGround 1e+12 60e-9
Initial VC1  4.4e6
TXT VC1 SCAle 1.0e-6
$V_marx (MV)
!
! Cap inductance, case & parasitic inductance, and ESR
! ESR = 0.3575 for the total Marx
!
RLSeries 0.3575 500e-9
!
! Switch resistance - Martin Model and switch inductance - the total gap for a single
!   switch from DWGs is 0.53 (1.346 cm) gap and 93 psig air X20 = 26.92 cm
!
! Initial switch resistance was chosen to be higher than that printed in the first
! few time steps so as to appear monotonically decreasing in R plots
! A careful few runs showed that 10 G looked best. In any event by 1 ns all of the 
! resistance values are the same.
!
RLSeries 10e9 50e-9
Var R2 Switch
!dielectric switchtime  gap        pressure     nswitch  nchannels
AIR           0.0                0.2692   7.3              8            1

TXT IR2 SCAle 1.0e-6
$I_marx (MA)
TXT R2
$R_switch ()
TXT ER2
$E_switch (J)
TXT QR2
$Q_switch (C)

!
! Output Marx header inducatance
!
RLSeries 0.00 80e-9

!
! Line 1 (PFL), 4-1.26 (6.5 ns), 1.26 (23.6 ns), 1.26-4 (6.5 ns)
!  (Actually, the starting impedance of the present PITHON-I PFL is likely higher than 4 )
!

TRLine EXP 6.5e-09 4.0 1.26
TRLine LIN 36.6e-09 1.26 1.26
TRLine EXP 6.5e-09 1.26 4.0

TXT VOUT SCAle 1.0e-6
$V_PFL_out (MV)
TXT IOUT SCAle 1.0e-6
$I_PFL_out (MA)
TXT EIN SCAle 1.0e-3
$E_PFL_in (kJ)
TXT EOUT SCAle 1.0e-3
$E_PFL_out (kJ)
TXT POUT SCAle 1.0e-6
$P_PFL_out (MW)

!
! PFL Output water switches
! 24 output switches, 7.173-cm gap, 120 nH each
!

RLSeries 10e9 5.0e-9
Var R2 Switch
!dielectric switchtime  gap             pressure   nswitch    nchannels
H2O          305e-09      0.07173    1.0              24             1

TXT IR2 SCAle 1.0e-6
$I_PFL_sw (MA)
TXT R2
$R_PFL_sw ()
TXT ER2 SCAle 1.0e-3
$E_PFL_sw (kJ)
TXT QR2
$Q_PFL_sw (C)

!
! Stray Switch capacitance
!
! Branch #2 location
TopBranch

!
! TL1 taper 0.972 - 0.95 (21.1 ns) and TL1 0.95  (28.7 ns)
! TL1 out taper 0.95  - 1.4  (9 ns)
!

TRLine LIN 21.1e-09  0.972 0.95

TXT VIN  SCAle 1.0e-6
$V_TL1_in (MV)
TXT IIN SCAle 1.0e-6
$I_TL1_in (MA)
TXT EIN SCAle 1.0e-3
$E_TL1_in (kJ)

TRLine LIN 28.7e-09 0.95  0.95
TRLine LIN 9.0e-09 0.95  1.4

TXT VOUT SCAle 1.0e-6
$V_TL1_out (MV)
TXT IOUT SCAle 1.0e-6
$I_TL1_out (MA)
TXT EOUT SCAle 1.0e-3
$E_TL1_out (kJ)
TXT POUT SCAle 1.0e-6
$P_TL1_out (MW)

!
! Pre-pulse Slab & switches
! 10 output switches, 1.27-cm gap, 40 nH each
!

RLSeries 10e9 4e-9
Var R2 Switch
!dielectric switchtime    gap           pressure     nswitch  nchannels
SF6           375e-09       0.0127      5.0               10           1

TXT IR2 SCAle 1.0e-6
$I_TL1_sw (MA)
TXT R2
$R_TL1_sw ()
TXT ER2 SCAle 1.0e-3
$E_TL1_sw (kJ)
TXT QR2
$Q_TL1_sw (C)

!
! Stray Pre-pulse slab Switch capacitance
!
! Branch #3 location

TopBranch

!
! TL2 Input Flare 1.69 - 0.744 (5.54 ns), TL1 0.744 (54.5 ns)
!

TRLine LIN 5.54e-09 1.69 0.744

TXT VIN SCAle 1.0e-6
$V_OTL_in (MV)
TXT IIN SCAle 1.0e-6
$I_OTL_in (MA)
TXT EIN SCAle 1.0e-3
$E_OTL_in (kJ)


TRLine LIN 53.4e-09 0.75 0.75

TXT VOUT SCAle 1.0e-6
$V_OTL_out (MV)
TXT IOUT SCAle 1.0e-6
$I_OTL_out (MA)
TXT EOUT SCAle 1.0e-3
$E_OTL_out (kJ)
TXT POUT SCAle 1.0e-6
$P_OTL_out (MW)

!
! Load resistance - Designed to match the output impedance of the OTL.
!

RCGround 0.744 0.0

TXT IR1 SCAle 1.0e-6
$I_load (MA)
TXT VR1 SCAle 1.0e-6
$V_load (MV)
TXT PR1 SCAle 1.0e-6
$P_load (MW)
TXT ER1 SCAle 1.0e-3
$E_load (kJ)

!
! End Main Branch (Branch #1)
!
! Level 2 Branches
!

! Branch #2

Branch

RCground 1e12 5.0e-10

! Branch #3

Branch

RCground 1e12 2.0e-10
