The XP Process

PPPL has implemented a process for evaluating proposals for experiments on TFTR. Experimental proposals (XPs) are first presented to and reviewed by a selected task force. This initial review is informal, and is intended to be wide-ranging. Often an experiment is changed significantly on the basis of review within the task force. All aspects of the proposed experiment are reviewed, but the important issues tend to fall into one of the following categories:

• Does the experiment address an important question in tokamak physics?
• Does the proposed experiment make use of unique TFTR capabilities? Could it be done elsewhere?
• Can the proposed experiment actually answer the questions it seeks to address, e.g. do we have the necessary diagnostics?
• Are the proposed machine conditions (R, a, B_t, I_p, P_b, P_rf, , , W_tot) feasible and are they consistent with diagnostic limitations, e.g. the CHERS diagnostic for measuring T_i and requires that sources from beamline 5 be injected.
• What limiter conditions are required, low recycling or highly saturated with deuterium?
• What can be done to minimize the risk of disruption?
• How much tritium does the experiment require?
• Optimization of the proposed sequence of shots, e.g., how to order the shots by plasma current, heating power, tritium usage, etc.
• Can the shot list be reduced? The XP proposer is generally asked to identify the highest priority shots, to be prepared for the possibility that the allocated run time is later decreased due to scheduling or technical difficulties.

Once approved, the XP is stamped with an XP number and becomes an offcial TFTR document. Subsequent changes to the proposed shot conditions in an XP must be approved in writing, on a special form, by Kevin Mcguire or Rich Hawryluk. In practice, this requirement has not proven to be a significant impediment.