R. Tomala

Chalmers University of Technology, Goeteborg, Västra Götaland, Sweden

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Publications (3)4.66 Total impact

  • R. Tomala · U. Jordan · D. Anderson · M. Lisak ·
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    ABSTRACT: In the present work, the microwave breakdown threshold in a gas-filled spherical resonator, is determined for the case when the cavity is excited in its lowest order mode, which implies that the microwave field strength depends on both radius and azimuthal angle. A semi-analytical approximation of the breakdown threshold is found using a direct variational approach. The variational predictions are compared with the results of full numerical calculations and demonstrate very good agreement
    Beiträge aus der Plasmaphysik 05/2006; 46(4):287 - 293. DOI:10.1002/ctpp.200610005 · 0.84 Impact Factor
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    ABSTRACT: The concept of effective diffusion length, as a means to characterize diffusion losses in calculations of microwave breakdown in radio frequency (RF) devices with inhomogeneous electric fields, is discussed in detail with emphasis on geometrical situations where the inhomogeneity of the microwave electric field plays an important role for the breakdown threshold. In particular, good analytical approximations are found for the microwave breakdown threshold field, in a number of different geometrical situations. Finally, an explicit experimental example demonstrates how the effective diffusion length in a coaxial resonant filter structure can be inferred from a set of breakdown threshold data obtained for different pressures.
    IEEE Transactions on Plasma Science 05/2006; 34(2-34):421 - 430. DOI:10.1109/TPS.2006.872189 · 1.10 Impact Factor
  • R Tomala · U Jordan · D Anderson · M Lisak ·
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    ABSTRACT: This paper investigates the microwave breakdown threshold in a circular waveguide excited in the lowest order (TE11) mode, where the electric field strength depends on both the radius and the azimuthal angle. This analysis complements and extends previous investigations of breakdown in cylindrical waveguides and resonators that have been restricted to circularly symmetric waveguide modes so far. A simple analytical approximation of the breakdown threshold of the TE11 mode is found, using a direct variational approach. The predictions are compared with the results of numerical calculations and the agreement is found to be very good.
    Journal of Physics D Applied Physics 06/2005; 38(14):2378. DOI:10.1088/0022-3727/38/14/012 · 2.72 Impact Factor

Publication Stats

33 Citations
4.66 Total Impact Points

Top co-authors


  • 2005-2006
    • Chalmers University of Technology
      • Department of Earth and Space Sciences
      Goeteborg, Västra Götaland, Sweden