Analysis of toroidal rotation

To analyze rotation data, specify NLVPHI=.TRUE. and supply rotation either as angular rotation or velocity rotation. These UFILES can be either 1D, if only the rotation on-axis is known, or 2D if the entire profile is measured. Rotation profiles have prefix and suffix PREVP2/EXTVP2 for velocity (units of cm/s) and PREOMG/EXTOMG for angular velocity (units of rad/s). If only the rotation on axis is known, then this can be input in a UFILE with extension PREVPH/EXTVPH (units of cm/s).
If both timeseries and profile data are available, the profile data may be renormalized to the timeseries data by specifying both input Ufiles to TRDAT and setting the switch NLRNVP=.T. and the value of the major radius at which to renormalize, with the variable RMJRVP. If RMJRVP is not provided, then the normalization occurs at the midpoint of the plasma midplane intersection. The renormalization can be done either for angular rotation (rad/s) or rotation velocity (cm/s) input.
If only the values on axis are available, then users can define a shape by means of the variable XVPHI.

HINT: rather than using XVPHI, we recommend to define an analytic profile for the rotation and then rescale this profile, because of the large number of options available for analytic profiles.

NOTE on convention for the sign of rotation. Rotation data are not defined in absolute value with respect to a cartesian reference. They are instead defined positive or negative with respect to the direction of the plasma current. Thus, if NBI is present in the discharge, positive rotation means 'in the direction of NBI co-injection'.

Electrostatic field

By default, TRANSP sets the radial electrostatic potential - which is used in the fast ion orbit model - from the toroidal rotation data input using a zeroth-order approximation, based on the balance between the force due to the electrostatic field and the Lorenz force.

Neoclassical corrections to this 0-th order approximation can be included by setting the flag NLVWNC=T.
Another option is to give the radial electrostatic potential (in volts) directly as an input UFILE with extension PREVPO/EXTVPO and set the switch NLIVPO = .TRUE.. Note that, if the VPO UFILE is provided, but the flag is set to FALSE (which is the default), the electrostatic potential is not used, but only stored in the output for comparison with the calculated profile. The flags NLVWNC and NLIVPO are mutually exclusive, they cannot both be set to TRUE.

WARNING: There is no contribution from the poloidal velocity in the momentum balance equation in TRANSP. If you have good diagnostics data for validation and are interested in contributing to this part of the code, please reach out to the TRANSP development team. We will be happy to work with you on this implementation.

Momentum Convection