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Josephson Junctions

General Form:
bname n+ n- [np] [modname] [ic=v1,p1] [vj=v1] [phi=p1] [area=val]
[control=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 2.17.12 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.

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.

See the Josephson junction model description in 2.17.12 for more information.


next up previous contents index
Next: Device Models Up: Superconductor Devices Previous: Superconductor Devices   Contents   Index
Stephen R. Whiteley 2006-10-23