MARFEs are experimentally studied using spectroscopic techniques to determine their internal characteristics. We find the local density and temperature in the MARFE to be $(2–3)\times {10}^{21}\mathrm{m}{}^{-3\mathrm{}}$ and 0.7–1.0 eV, respectively. The volume recombination rate is also large in the MARFE, $(5–10)\times {10}^{22}\mathrm{s}{}^{-1\mathrm{}}$, similar in magnitude to the plasma source rate in the core. Because this plasma sink is located in confined regions of the plasma, the MARFE acts like a limiter; ions “recycle” from the MARFE as neutrals. These characteristics have not been predicted by current models.

• Received 7 May 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.1007