Mazzaglia, M. Castro, G. Celona, L. Gammino, S. Mascali, D. Miracoli, R. Naselli, E. Reitano, R. Stefan, S.B. Torrisi, G. Ursel, U.F. JACoW Publishing Geneva, Switzerland 978-3-95450-196-0 10.18429/JACoW-ECRIS2018-TUP25 English 144-147 TUP25 plasma ECR electron diagnostics experiment Contribution to a conference proceedings 2019 2019-01 https://doi.org/10.18429/JACoW-ECRIS2018-TUP25 http://jacow.org/ecris2018/papers/tup25.pdf This work presents the multiple diagnostics characterization of the plasma in an axis-symmetric simple mirror trap as a function of magnetic field profile (mirror ratios and magnetic field gradient), neutral gas pressure and microwave power. The simultaneous use of Optical Emission Spectroscopy, Langmuir Probe and X-ray diagnostics allows the characterization of the whole electron energy distribution function (EEDF), from a few eV to hundreds of keV. Results show non-linear behaviours under small variations of even one source parameter and strong influence of EEDF on the Bmin/BECR ratio. Benefit and next developments will be highlighted.