Editing Plasma diagnostics (section)

===Ball-pen probe===
{{main|Ball-pen probe}}
A [[ball-pen probe]] is novel technique used to measure directly the [[plasma potential]] in magnetized plasmas. The probe was invented by [[Jiří Adámek]] in the Institute of Plasma Physics AS CR in 2004.<ref>{{Cite journal|last1=Adámek|first1=J.|last2=Stöckel|first2=J.|last3=Hron|first3=M.|last4=Ryszawy|first4=J.|last5=Tichý|first5=M.|last6=Schrittwieser|first6=R.|last7=Ionită|first7=C.|last8=Balan|first8=P.|last9=Martines|first9=E.|date=2004|title=A novel approach to direct measurement of the plasma potential|journal=Czechoslovak Journal of Physics|language=en|volume=54|issue=S3|pages=C95–C99|doi=10.1007/BF03166386|issn=0011-4626|bibcode=2004CzJPS..54C..95A|s2cid=54869196}}</ref> The [[ball-pen probe]] balances the electron saturation current to the same magnitude as that of the ion saturation current. In this case, its [[Langmuir probe|floating potential]] becomes identical to the plasma potential. This goal is attained by a ceramic shield, which screens off an adjustable part of the electron current from the probe collector due to the much smaller gyro–radius of the electrons. The [[electron temperature]] is proportional to the difference of ball-pen probe(plasma potential) and Langmuir probe (floating potential) potential. Thus, the electron temperature can be obtained directly with high temporal resolution without additional [[power supply]].