Helicon sources are very effective in many aspects and are applicable in various science and technology fields, since they can supply high-density (∼ 1013 cm-3) plasmas with flexible operating parameters. In this paper, we characterize developed, featured sources in various sizes along with a discussion on a particle production efficiency. This activity was performed within the HEAT (Helicon Electrodeless Advanced Thruster) project aiming at development of the systems that can realize the schemes of completely electrodeless plasma production and acceleration. This is expected to mitigate a problem of finite life time inherent to electrodic plasma propulsion tools. Experimental and theoretical approaches to implementation of such the schemes are presented.