example_vops

pypulseqpp.safety.example_vops()

Build a synthetic VOP model, for demonstrations and tests only.

An num_channels-loop array around a uniform cylinder at 3 T, in a 2D quasi-static model: each loop is a pair of opposed axial wires, and the electric field is -j omega A_z of their vector potential. Local SAR matrices are averaged over 12 mm disks on a coarse grid and used as the VOPs uncompressed; the global matrix is averaged over the whole cylinder.

No tissue, no coil coupling and no conservative field are modelled, so the numbers are plausible in scale and nothing more.

Parameters:

num_channels (int, default=8) – Transmit channels the synthetic array has.

Returns:

model, a VopModel in W/kg per V^2; drive_per_hz, the drive in volts per channel that gives 1 Hz of B1+ at the centre in circular polarisation; and cp_shim, that polarisation’s weights.

Return type:

SimpleNamespace