Empirical scaling relations are deduced describing the neutron emission from TFTR• supershots using a data base that includes all of the supershot plasmas (525) from the 1990 campaign. A physics-based scaling for the neutron emission is derived from the dependence of the central plasma parameters on machine settings and the energy confinement time. Thi:.scaling has been used to project the fusion rate for equivalent DT plasmas in TFTR, aad to explore machine operation space which optimizes the fusion rate. Increases in neutron emission are possible by either increasing the toroidal magnetic field or further improving the limiter conditioning.. 1MIT Plasma Fusion Center, Cambridge, MA 02139 I. INTRODUCTION '4,One goal of the TFTR experimental research program is to achieve scientific breakeven wherein the fusion power produced equals the power required to heat the plasma. Presently, the highest performance TFTR deuterium plasmas are the supershot plasmas [1] which have produced equivalent QDT values _ 1/3 [2] (where "equivalent" is a projection that is defined in Sec. 8). Clearly, there is a need to operate the supershot plasma in a manner that will further optimize its fusion performance.This paper evaluates the statistical dependence of the d(d,n)ZHe fusion neutron emission from TFTR deuterium supershots upon the TFTR machine settings (e.g., plasma current, toroidal magnetic field, neutral beam power, etc.). Empirical and physics-based scaling relations are derived and compared to the neutron emission as well as to that predicted by Q one-dimensional transport codes. The supershot neutron emission is described in terms of a zero-dimensional model which identifies the variables related to the underlying physics of the fusion reactions. This model was used to evaluate equivalent fusion rates for DT plasmas and to suggest machine conditions for optimal performance.The analysis indicates that the primary limitation of the TFTR supershots is the apparent f3-1imit of the supershots when the plasma energy content is about 0.S of the Troyon value [3].Above this limit, TFTR supershots experience some disruptions. Even sporadic disruptions make experiments in the supershot regime difficult due to the sensitivity of supershots to the wall conditions. Another conclusion from the statistical analysis is that the deuterium neutron emission was independent of the neutral beam voltage (from 85 kV to 105 kV).However, considerable improyement was achieved by conditioning the walls with lithium pellet injection. A further improvement is projected by increasing the toroidal magnetic 2 field.The organization of this paper is first to describe the database. Scaling relations are then derived for the neutron emission based upon entirely empirical regression analysis.The measured neutron rates are then compared with those predicted by one-dimensional transport calculations.A zero-dimensional model for the neutron emission is then derived.TFTR supershot scaling for the relevant plasma parameters that describe the classical physics o...

The complete ion cyclotron range of frequency (ICRF) heating system for the Tokamak Fusion Test Reactor (TFTR) [ Fusion Tech. 21, 1324 (1992) ], consisting of tour antennas and six generators designed to deliver 12.5 MW to the TFTR plasma, has now been installed. Recently a series of experiments has been conducted to explore the effect of ICRP heating on the performance of low recycling, Supershot plasmas in minority and non-resonant electron heating regimes. The addition of up to 7.4 MW of ICRF power to full size (R-2.6 m, a0 .95 m), helium-3 minority, deuterium Supershots heated with up to 30 MW of deuterium neutral beam injection has resulted in a significant increase in core electron temperature (ATe=3-4 keV). Simulations of equivalent deuterium-tritium (D-T) Supershots predict that such ICRF heating should result in an increase in [la(0)~30%. Direct electron heating has been observed and has been found to be in agreement with theory. ICRF heating has also been coapled to neutral beam heated plasmas fueled by frozen deuterium pellets. In addition ICRF heated energetic iota tails have been used to simulate fusion alpha particles in high recycling plasmas. Up to 11.4 MW of ICRF heating has been coupled into a hydrogen minority, high recycling helium plasma and the f'trst observation of the toroidal Alfv6n eigenmode (TAE) instability driven by the energetic proton tail has been made in this regime.