Impact of bivariate energy and angular atomic impact spectra on tungsten erosion in JET

Abstract The erosion of tungsten plasma-facing components due to charge-exchange atoms, predicted to be the dominant cause of the observed W radiation in most JET plasmas with a Be/W wall (formerly ITER-like wall), is quantified by the first EIRENE simulations of the bivariate energy-angular impact spectrum and the incident flux of deuterium and tritium atoms. The tungsten erosion rate due to the bivariate impact spectrum in the JET outer vertical divertor corresponds to a constant effective impact angle of 43 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mo>∘</mml:mo> </mml:msup> </mml:mrow> </mml:math> . Assuming independent univariate energy and angular distributions instead of the bivariate spectrum causes a predicted increase of order 10% in the tungsten influx and the core radiated power. The predicted tungsten sputtering rate due to tritium atoms is 2–6 times the sputtering rate by deuterium atoms in similar edge plasmas. A hypothetical replacement of all JET first-wall materials with tungsten is predicted to raise the total radiated power by 60% in a diverted H-mode scenario if the added radiation is offset by additional heating and the plasma conditions are unchanged.