A comparison between laboratory and space experiments on Alfven´s CIV effect

Laboratory experiments on Alfven´s critical ionization velocity (CIV) effect have established the reality of the CIV effect and determined the parameter limits within which the effect can be expected in the laboratory for different combinations of plasma and neutral gas species: velocity, magnetic field strength, and neutral gas and plasma density. However, in the laboratory experiments there are always walls and usually electrodes present, and the available parameter regime is such that the details inside the CIV process are difficult to study. Such studies can better be made in ionospheric release experiments, where waves and particle spectra can be directly measured inside the interaction region. Injection experiments are also better suited to study the momentum exchange process between the CIV region and a larger surrounding plasma