Experimental observations concerning the formation of a high‐density plasma in an inductively coupled radio frequency (11.4 MHz) discharge in argon are described. These observations are complemented by probe measurements that provide a quantitative description of plasma properties over an useful range of vapor pressure, 0.02–0.2 Torr, and rf power, 50–400 W. It is shown that a dense plasma of the order of 1012cm−3can be easily formed, having the configuration of a luminous plasmoid embedded in a low‐density, 1010cm−3, diffuse plasma.