Abstract. The magnetic-octupole (M3) and electric-quadrupole (E2) transitions between the ground state 3d¹⁰¹S₀ and the lowest excited 3d⁹4s(5/2, 1/2)J = 3 and J = 2 states in the Ni-like tungsten are shown to exhibit a strong dependence on electron density N_e in the range of values typical for tokamak plasmas. Remarkably, the total intensity of these overlapping lines remains almost constant, which may explain the strong emission in the 7.93 Å line observed in tokamak experiments (Neu R et al 1997 J. Phys. B: At. Mol. Opt. Phys. 30 5057). Utilization of the M3 and E2 line ratios for density diagnostics in high-spectral-resolution experiments is discussed as well.

Print publication: Issue 11 (14 June 2007)
Received 2 April 2007, in final form 5 April 2007
Published 23 May 2007