WIAS Preprint No. 2247, (2016)

Thermistor systems of p(x)-Laplace-type with discontinuous exponents via entropy solutions


  • Bulíček, Miroslav
  • Glitzky, Annegret
    ORCID: 0000-0003-1995-5491
  • Liero, Matthias
    ORCID: 0000-0002-0963-2915

2010 Mathematics Subject Classification

  • 35J92 35Q79 35J57 80A20


  • Sobolev spaces with variable exponent, existence of weak solution, entropy solution, thermistor system, p(x)-Laplacian, heat transfer




We show the existence of solutions to a system of elliptic PDEs, that was recently introduced to describe the electrothermal behavior of organic semiconductor devices. Here, two difficulties appear: (i) the elliptic term in the current-flow equation is of p(x)-Laplacian-type with discontinuous exponent p, which limits the use of standard methods, and (ii) in the heat equation, we have to deal with an a priori L1 term on the right hand side describing the Joule heating in the device. We prove the existence of a weak solution under very weak assumptions on the data. Our existence proof is based on Schauder's fixed point theorem and the concept of entropy solutions for the heat equation. Here, the crucial point is the continuous dependence of the entropy solutions on the data of the problem.

Appeared in

  • PDE 2015: Theory and Applications of Partial Differential Equations (PDE 2015), H.-Chr. Kaiser, D. Knees, A. Mielke, J. Rehberg, E. Rocca, M. Thomas, E. Valdinoci, eds., vol. 10 of Discrete and Continuous Dynamical Systems, Series S, American Institute of Mathematical Sciences, Springfield, 2017, pp. 697--713.

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