Online and FREE access to plasma physics experiments

Remote controlled laboratories had a great push during the COVID-19 pandemic. In fact, they were already out there but lacking in visibility. This external trigger pushed the academy to face a global challenge to start offering remote experiments more consistently and maturely. Instituto Superior Técnico (IST) has been offering several remote experiments since 2000 but with the need for an update due to technological aging. As such, the framework for remote experiments in education (FREE) was created based on new web technologies. In addition to the most diverse experiments that had already been developed, FREE includes two experiments that aimed at advanced-level physics students: the Langmuir probe and the electromagnetic (EM) cavity. Both allow users to configure the various parameters and to access the results in real time or check back later. All this access is done using a browser (on a PC or mobile phone) without the need to install additional software. The results of an experimental execution are stored in a database and are downloadable, allowing users to do various analyses and to determine the corresponding plasma density and temperature. In this paper, we will introduce how FREE was used in the implementation of both experiments and give an insight into their didactic approach, such as: (i) how to perform an experimental execution, (ii) the typical data set obtained with, and (iii) the corresponding analysis necessary for the user to retrieve information from it.