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## Josephson Junctions

General Form:
bname n+ n- [np] [modname] [parameters ...]

Parameter Name Description
pijj=1|0 Whether the device is a pi'' junction.
area=val Scale factor that multiplies all currents and other values, effectively modifying the junction area.
mfactor=val Alias for area.
ic=vj,phi The initial junction voltage and phase (initial condition) for transient analysis.
vj=vj The initial junction voltage (initial condition) for transient analysis.
ic_v=vj Alias for vj.
phi=phi The initial junction phase (initial condition) for transient analysis.
ic_phase=phi Alias for phi.
control=name Controlling voltage source or inductor name.

Examples:
b1 1 0 10 jj1 area=2
bxx 2 0 type1 control=l3
b2 4 5 ybco phi=1.57

The n+ and n- are the positive and negative element nodes, respectively. These are followed by an optional phase node. The phase node, if specified, generally should have no other connections in the circuit, but the voltage of this node gives the phase of the junction in radians. The modname is the name of the Josephson junction model. If no model is specified, then a default model is used (see the description of the Josephson model in 2.17.2 for the default values). Other (optional) parameters follow in any order. The initial phase (in radians) and voltage of the junction can be specified either as a vector or independently. If not specified, the initial junction voltage and phase are taken to be zero. Transient analysis of circuits containing Josephson junctions always starts from initial conditions. The junction area (effectively the number of devices in parallel) can be specified with the area parameter. The control current source can be specified with the control parameter. The name in the control specification represents the name of either a voltage source or inductor which appears elsewhere in the circuit. The control parameter is only needed if critical current modulation is part of the circuit operation, and is only relevant to Josephson junction model types that support critical current modulation.

If the pijj parameter is given and set to a nonzero integer value, the device instance will behave as a pi'' junction. This type of junction has a ground state with phase rather than 0. The value given on the device line (if any) overrides the value given in the model.

When Josephson junctions are present in the circuit, only transient analysis may be performed, and the transient uic parameter will be set implicitly. The time step is determined by junction phase change by default, in accordance with the setting of the dphimax option variable. If the variable nojjtp is set, the truncation error timestep predictor is used as is the case when Josephson junctions are not present.

Next: Josephson Junction Model Up: Superconductor Devices Previous: Superconductor Devices   Contents   Index
Stephen R. Whiteley 2017-03-28