Practical solutions for reliable triple probe measurements in magnetized plasmas

Theiler, C.; Furno, I.; Kuenlin, A.; Marmillod, Ph.; Fasoli, A.
January 2011
Review of Scientific Instruments;Jan2011, Vol. 82 Issue 1, p013504
Academic Journal
The triple probe method to obtain local, time-resolved measurements of density, electron temperature and plasma potential is investigated in detail. The difficulties in obtaining reliable measurements with this technique are discussed and overcome. These include phase delay errors, ion sheath expansion and limited bandwidth due to stray capacitance to ground. In particular, a relatively simple electronic circuit is described to strongly reduce stray capacitance. Measurements with the triple probe are presented in a plasma characterized by interchange-driven turbulence in the TORPEX device. The measured time-averaged and time-dependent, conditionally averaged parameters are cross-checked with other Langmuir probe based techniques, and show good agreement. Triple probe measurements show that electron temperature fluctuations are sufficiently large, such that the identification of plasma potential fluctuations with fluctuations of the floating potential is not a good approximation. Over a large radial region, the time-averaged fluctuation-induced particle flux can, however, be deduced from floating potential only. This is because the phase shift between density and electron temperature is close to zero there and temperature fluctuations do not give rise to a net radial particle transport.


Related Articles

  • Measuring the plasma density of a ferroelectric plasma source in an expanding plasma. Dunaevsky, A.; Fisch, N. J. // Journal of Applied Physics;5/1/2004, Vol. 95 Issue 9, p4621 

    The initial density and electron temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements in an expanding plasma. The method exploits negative charging of the floating probe capacitance by fast flows before the expanding plasma reaches the probe....

  • Three-dimensional fluid simulations of a simple magnetized toroidal plasma. Ricci, Paolo; Rogers, B. N. // Physics of Plasmas;Sep2009, Vol. 16 Issue 9, p092307 

    Three-dimensional fluid simulations are performed in a simple magnetized toroidal plasma, in which vertical and toroidal magnetic fields create helicoidal magnetic field lines that terminate on the torus vessel. The simulations are carried out in the three-dimensional flux tube that wraps around...

  • On the origin of turbulent fields in interplanetary plasmas. Lazar, M. // AIP Conference Proceedings;9/8/2008, Vol. 1043 Issue 1, p318 

    Solar coronal mass ejections are prominent example of interpenetrating particle streams with different properties: densities, speeds, temperature and composition. Such counterstreaming plasmas are quickly unstable leading to the excitation of the electrostatic and electromagnetic instabilities....

  • Multiparameter Measurement Utilizing Poloidal Polarimeter for Burning Plasma Reactor. Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi; Kusama, Yoshinori // AIP Conference Proceedings;2014, Vol. 1612, p61 

    The authors have made the basic and applied research on the Polarimeter for plasma diagnostics. Recently, the authors have proposed an application of multiparameter measurement (magnetic field, B, electron density, ne, electron temperature, Te, and total plasma current, Ip) utilizing polarimeter...

  • Plasma parameters in the upgraded Trimyx-M Galathea. Morozov, A. I.; Bugrova, A. I.; Bishaev, A. M.; Lipatov, A. S.; Kozintseva, M. V. // Technical Physics;Dec2007, Vol. 52 Issue 12, p1546 

    Results are presented from measurements of the plasma parameters in the upgraded Trimyx-M Galathea. After the barrier magnetic field and the energy of the injected hydrogen plasma bunch were increased to B bar ∼ 0.1 T and W 0 ≈ 200 J, respectively, the following plasma parameters were...

  • Interaction between turbulence and a nonlinear tearing mode in the low β regime. Militello, F.; Waelbroeck, F. L.; Fitzpatrick, R.; Horton, W. // Physics of Plasmas;May2008, Vol. 15 Issue 5, p050701 

    The interaction between turbulence and a nonlinear tearing mode is investigated numerically using a 2D electrostatic model. Turbulence is found to cause transitions between the different roots for the propagation velocity of the mode. The transitions take the mode towards roots with slower...

  • Experiments on the longitudinal ion momentum balance in a magnetized plasma. Vogels, J. M. M. J.; de Haas, J. C. M.; Schram, D. C.; Lunk, A. // Journal of Applied Physics;1/1/1986, Vol. 59 Issue 1, p71 

    Presents a study which focused on experiments on the longitudinal ion momentum balance in a magnetized plasma. Theory of the axial momentum balance; Experimental arrangement; Discussion of the influence of turbulence.

  • Distribution of particle velocity perpendicular to magnetic field in turbulent plasma. Fujisawa, A. // Physics of Fluids B: Plasma Physics;May93, Vol. 5 Issue 5, p1482 

    In a turbulent magnetized plasma a relationship between velocity distribution of particles and its stochastic electric field is studied by solving the equation of motion both analytically and numerically. The distribution of velocity perpendicular to magnetic field direction is shown to be...

  • Influence of resonant magnetic perturbations on plasma edge turbulence. Castro, R.M.; Heller, M.V.A.P.; Caldas, I.L.; Brasilio, Z.A.; da Silva, R.P.; Nascimento, I.C. // Physics of Plasmas;Feb97, Vol. 4 Issue 2, p329 

    Reports on alterations on plasma-edge equilibrium profiles and on edge turbulence, and anomalous transport induced by resonant perturbing magnetic fields in the TBR tokamak. Computation of electrostatic edge parameters; Effects of the perturbation on the linear correlation between electrostatic...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics