# Coordinates¶

The tokamak is a curvilinear device which can be described in a number of coordinate systems: the Cartesian coordinates $$(X,Y,Z)$$, the cylindrical coordinates $$(R, Z, \phi)$$, the toroidal coordinates $$(r, \theta, \phi)$$ and many more. PLEQUE supports all of the above and more, see the Straight Field Lines example notebook.

## Accepted coordinates types¶

1D - coordinates

Coordinate Code Note
$$\psi_\mathrm{N}$$ psi_n Default 1D coordinate
$$\psi$$ psi
$$\rho$$ rho $$\rho = \sqrt{\psi_n}$$

2D - coordinates

Coordinate Code Note
$$(R, Z)$$ R, Z Default 2D coordinate
$$(r, \theta)$$ r, theta Polar coordinates with respect to magnetic axis

3D - coordinates

Coordinate Code Note
$$(R, Z, \phi)$$ R, Z, phi Default 3D coordinate
$$(X, Y, Z)$$ X, Y, Z