Measurements of the poloidal magnetic and radial electric field profiles in ASDEX Upgrade and JET

  • J. Hobirk
  • N. C. Hawkes
  • P. J. McCarthy
  • D. Merkl
  • R. C. Wolf
  • ASDEX Upgrade Team


In magnetic confinement devices the plasma confinement and stability are determined by the magnetic field configuration consisting of toroidal and poloidal field components. In tokamaks the poloidal magnetic field is determined by the profile of the toroidal current. In addition to the Faraday rotation polarimetry [1, 2] the Motional Stark Effect (MSE) has become a routine diagnostic technique to determine the current density distribution [3, 4, 5, 6, 7, 8, 9, 10, 11]. The MSE diagnostic utilizes the Doppler shifted neutral beam emission spectrum which is dominated by the Stark effect due to the electrical field experienced by the fast atoms in their rest frame which is mainly the Lorentz electric field \( \overrightarrow v _{beam} \times \overrightarrow B \). The orientation of this Lorentz electric field is measured, and incorporated in an equilibrium reconstruction, which yields profiles of poloidal magnetic field, current density, safety factor q or poloidal flux. In this paper the diagnostic principle and its implementation on ASDEX Upgrade and JET will be presented in sections two and three. The results of the diagnostic will be discussed in section 4 and the influence of another beam source on the measurement in section 5. Since the MSE diagnostic is sensitive to electric fields in general this opens the possibility to measure also internal electric fields such as the radial electric field [12, 13]. If E r /u beam becomes of the order of B pol then E r can no longer be neglected which is the case in particular for discharges with an internal transport barrier (ITB). The measurement of E r may also be applicable to stellarators where the magnetic field configuration deviates only slightly from the known vacuum configuration. The stronger field line curvature could however increase the requirements regarding the spatial resolution of a MSE diagnostic. First measurements of the radial electric field will be presented in section 6 and a summary will follow in section 7.


Beam Line Beam Source Poloidal Field Neutral Beam Toroidal Magnetic Field 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [1]
    H. Soltwisch, Rev. Sci. Intrum.57, 1939 (1986).ADSCrossRefGoogle Scholar
  2. [2]
    H. R. Koslowski and H. Soltwisch, Fusion Engineering and Design34–35, 143 (1997).CrossRefGoogle Scholar
  3. [3]
    F. M. Levinton et al., Phys. Rev. Lett.63, 2060 (1989).ADSCrossRefGoogle Scholar
  4. [4]
    D. Wróblewski et al., Rev. Sci. Instrum.61, 3552 (1990).ADSCrossRefGoogle Scholar
  5. [5]
    D. Wróblewski and L. L. Lao, Rev. Sci. Instrum.63, 5140 (1992).ADSCrossRefGoogle Scholar
  6. [6]
    F. M. Levinton, S. H. Batha, M. Yamada, and M. C. Zarnstorff, Phys. Fluids B5, 2554 (1993).ADSCrossRefGoogle Scholar
  7. [7]
    B. W. Rice, Fusion Engineering and Design34–35, 135 (1997).CrossRefGoogle Scholar
  8. [8]
    R. C. Wolf, P. J. McCarthy, F. Mast, and H. P. Zehrfeld, Europhysics Conference Abstracts (Proc. 24th Eur. Conf. Berchtesgaden 1997)21A, 1509 (1997).Google Scholar
  9. [9]
    B. C. Stratton, D. Long, R. Palladino, and N. C. Hawkes, Rev. Sci. Instrum. 70, 898 (1999).ADSCrossRefGoogle Scholar
  10. [10]
    N. C. Hawkes et al., Rev. Sci. Instrum.70, 894 (1999).ADSCrossRefGoogle Scholar
  11. [11]
    F. M. Levinton, Rev. Sci. Instrum.70, 810 (1999).ADSCrossRefGoogle Scholar
  12. [12]
    B. W. Rice, K. H. Burell, L. L. Lao, and Y. R. Lin-Liu, Phys. Rev. Let.79, 2694 (1997).ADSCrossRefGoogle Scholar
  13. [13]
    M. C. Zarnstorff, F. M. Levinton, S. H. Batha, and E. J. Synakowski, Phys. Plasmas4, 1094 (1997).ADSCrossRefGoogle Scholar
  14. [14]
    W. Mandl, R. C. Wolf, M. G. von Hellermann, and H. P. Summers, Plasma Phys. Contr. Fusion35, 1373 (1993).ADSCrossRefGoogle Scholar
  15. [15]
    D. Voslamber, Rev. Sci. Instrum.66, 2892 (1995).ADSCrossRefGoogle Scholar
  16. [16]
    T. Soetens, R. Jaspers, and E. Desoppere, Rev. Sci. Instrum.70, 890 (1999).ADSCrossRefGoogle Scholar
  17. [17]
    R. C. Wolf, D. Ciric, and R. W. T. König, JET-P68, (1994).Google Scholar
  18. [18]
    K. H. Burrel, Phys. Plasmas4, 1499 (1997).MathSciNetADSCrossRefGoogle Scholar
  19. [19]
    H. Meister et al., this conference (P3.035) (2000).Google Scholar
  20. [20]
    W. Herrmann, Phys. Rev. Lett.75, 4401 (1995).ADSCrossRefGoogle Scholar
  21. [21]
    S. Günter et al., Phys. Rev. Lett.84, 3097 (2000).ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • J. Hobirk
    • 1
  • N. C. Hawkes
    • 2
  • P. J. McCarthy
    • 3
  • D. Merkl
    • 1
  • R. C. Wolf
    • 1
  • ASDEX Upgrade Team
  1. 1.Max-Planck-Institut für PlasmaphysikEURATOM AssociationGarchingGermany
  2. 2.Euratom/UKAEA AssociationCulham Science CentreAbingdonUK
  3. 3.Physics DepartmentCorkIreland

Personalised recommendations