Return To: Session EX/P1 - JET, Small Tokamaks, Other Confinement
Prev Page: (EX/P1-07) Limiter Biasing Effects on the Magnetohydrodynamic Behavior
Next Page: (EX/P1-09) Reduction of Divertor Heat Load in JET

(EX/P1-08) Type I ELM Energy and Particle Losses in JET H Modes and Implications for ITER

A. Loarte¹⁾, JET EFDA Contributors
 
¹⁾ EFDA-CSU Garching Max-Planck-Institut für Plasmaphysik, Garching, European Commission

Abstract.  JET has achieved discharges that meet the ITER requirements ( q₉₅, Z_eff, < n_e > /n_GW, H98, etc.) in Type I ELMy H-modes at high triangularities. One of the problems for the full extrapolability of these discharges to ITER is the transient energy loads onto the divertor target associated with Type I ELMs that may lead to a limitation of the ITER target lifetime. Type I ELM energy losses decrease with increasing pedestal density and decreasing pedestal temperature, for a wide range of JET ELMy H-mode plasmas. The normalised ELM energy losses (DWELM/Wped) are well correlated with the pedestal plasma collisionality ( $\nu^{\ast}_{ped}$). The reduction of DWELM/Wped with increasing $\nu^{\ast}_{ped}$ is mostly due to the reduction of the temperature drop that the ELM causes (i.e., conductive losses). ELM particle losses (leading to convective losses) seem to be independent of $\nu^{\ast}_{ped}$. Pure convective Type I ELMs have been observed in JET with a normalised energy loss of $\sim$ 0.05, which is within the acceptable values estimated for ITER ($\sim$ 0.07). On the basis of the JET ELM results, the implications for the expected ELM size and its convective/conductive nature in ITER will be described.

Read the full paper in PDF format.