Measurement of Dielectronic Recombination Rates for the Iron Ions Fe IX-XI

Iron is injected into a well-diagnosed $\theta$-pinch plasma. The intensities of lines from various ionization stages are measured as functions of time and interpreted by means of a time-dependent corona ionization-recombination model. Effective coefficients for dielectronic recombination at electron densities $N_e\approx 3\times {10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$ are equal to or smaller than presently accepted theoretical values for low-density plasmas. Rate coefficients for ionization tend to be smaller than theoretical values.