In order to establish the conditions required for the formation of a neutral loop discharge (NLD) plasma, the distributions of excited atoms that are closely related to that of the ionization rates were measured under various discharge conditions. Also, computer-based simulations in three dimensions were used to examine the experimental results obtained. The measurements of the distributions of excited atoms were performed using laser-induced fluorescence and optical emission spectroscopy(s). The results of the measurements were consistent with the theoretically predicted dependencies of electron heating on the magnetic field strength, electric field, frequency and NL radius. In addition, it was found that the plasma localization increased with the normalized rf electric field (F0), which can be used to characterize the localization degree of the plasma production region.