@article{FeudelSeehafer1995, author = {Feudel, Fred and Seehafer, Norbert}, title = {Bifurcations and pattern formation in two-dimensional Navier-Stokes fluid}, year = {1995}, language = {en} } @article{SeehaferGalantiFeudeletal.1996, author = {Seehafer, Norbert and Galanti, B. and Feudel, Fred and R{\"u}diger, Sten}, title = {Symmetry breaking bifurcations for the magnetohydrodynamic equations with helical forcing}, year = {1996}, language = {en} } @article{RustCrookerGoldetal.1996, author = {Rust, David M. and Crooker, N. U. and Gold, R. E. and Golub, Leon and Hundhausen, A. J. and Lanzerotti, L. J. and Lazarus, A. J. and Seehafer, Norbert and Zanetti, L. J.}, title = {Heliospheric lins explorer (HELIX)}, year = {1996}, language = {en} } @article{Seehafer1996, author = {Seehafer, Norbert}, title = {Nature of the alpha effect in magnetohydrodynamics}, year = {1996}, language = {en} } @article{SeehaferZienickeFeudel1996, author = {Seehafer, Norbert and Zienicke, Egbert and Feudel, Fred}, title = {Absence of magnetohydrodynamic activity in the voltage-driven sheet pinch}, year = {1996}, language = {en} } @article{SeehaferFeudelSchmidtmann1996, author = {Seehafer, Norbert and Feudel, Fred and Schmidtmann, Olaf}, title = {Nonlinear dynamo with ABC forcing}, year = {1996}, language = {en} } @article{FeudelSeehaferSchmidtmann1996, author = {Feudel, Fred and Seehafer, Norbert and Schmidtmann, Olaf}, title = {Bifurcation phenomena of the magnetofluid equations}, year = {1996}, abstract = {We report on bifurcation studies for the incompressible magnetohydrodynamic equations in three space dimensions with periodic boundary conditions and a temporally constant external forcing. Fourier representations of velocity, pressure and magnetic field have been used to transform the original partial differential equations into systems of ordinary differential equations (ODE), to which then special numerical methods for the qualitative analysis of systems of ODE have been applied, supplemented by the simulative calculation of solutions for selected initial conditions. In a part of the calculations, in order to reduce the number of modes to be retained, the concept of approximate inertial manifolds has been applied. For varying (increasing from zero) strength of the imposed forcing, or varying Reynolds number, respectively, time-asymptotic states, notably stable stationary solutions, have been traced. A primary non- magnetic steady state loses, in a Hopf bifurcation, stability to a periodic state with a non-vanishing magnetic field, showing the appearance of a generic dynamo effect. From now on the magnetic field is present for all values of the forcing. The Hopf bifurcation is followed by further, symmetry-breaking, bifurcations, leading finally to chaos. We pay particular attention to kinetic and magnetic helicities. The dynamo effect is observed only if the forcing is chosen such that a mean kinetic helicity is generated; otherwise the magnetic field diffuses away, and the time-asymptotic states are non-magnetic, in accordance with traditional kinematic dynamo theory.}, language = {en} } @article{SchmidtmannFeudelSeehafer1997, author = {Schmidtmann, Olaf and Feudel, Fred and Seehafer, Norbert}, title = {Nonlinear Galerkin methods for the 3D magnetohydrodynamic equations}, year = {1997}, language = {en} } @article{SeehaferSchumacher1997, author = {Seehafer, Norbert and Schumacher, J{\"o}rg}, title = {Squire's theorem for the magnetohydrodynamic sheet pinch}, year = {1997}, language = {en} } @article{ScheelSeehafer1997, author = {Scheel, S. and Seehafer, Norbert}, title = {Bifurcation to oscillations in three-dimensional Rayleigh-B{\´e}nard convection}, year = {1997}, language = {en} } @article{BraunFeudelSeehafer1997, author = {Braun, Robert and Feudel, Fred and Seehafer, Norbert}, title = {Bifurcations and chaos in an array of forced vortices}, year = {1997}, language = {en} } @article{Seehafer1998, author = {Seehafer, Norbert}, title = {Filaments and the solar dynamo}, isbn = {1-88673-370-8}, year = {1998}, language = {en} } @article{SeehaferFeudelGalanti1998, author = {Seehafer, Norbert and Feudel, Fred and Galanti, B.}, title = {Bifurcations in a magnetofluid with helical forcing}, isbn = {1-563-47284-8}, year = {1998}, language = {en} } @article{SchmidtmannFeudelSeehafer1998, author = {Schmidtmann, Olaf and Feudel, Fred and Seehafer, Norbert}, title = {Nonlinear Galerkin methods based on the concept of determining modes for the magnetohydrodynamic equations}, year = {1998}, language = {en} } @article{ZienickeSeehaferFeudel1998, author = {Zienicke, Egbert and Seehafer, Norbert and Feudel, Fred}, title = {Bifurcations in two-dimensional Rayleigh-B{\´e}nard convection}, year = {1998}, language = {en} } @article{SeehaferSchumacher1998, author = {Seehafer, Norbert and Schumacher, J{\"o}rg}, title = {Resistivity profile and instability of the plane sheet pinch}, year = {1998}, language = {en} } @article{RuedigerFeudelSeehafer1998, author = {R{\"u}diger, Sten and Feudel, Fred and Seehafer, Norbert}, title = {Dynamo bifurcations in an array of driven convectionlike rolls}, year = {1998}, language = {en} } @article{KurthsSeehaferSpahn1999, author = {Kurths, J{\"u}rgen and Seehafer, Norbert and Spahn, Frank}, title = {Nichtlineare Dynamik in der Physik : Forschungsbeispiele und Forschungstrends}, isbn = {3-540-65329- 5}, year = {1999}, language = {de} } @article{DemircanSeehafer1999, author = {Demircan, Ayhan and Seehafer, Norbert}, title = {Bifurcation to oscillations and chaos in rotating convection}, year = {1999}, language = {en} } @article{BrownCanfieldFieldetal.1999, author = {Brown, M. R. and Canfield, R. C. and Field, G. and Kulsrud, R. and Pevtsov, A. A. and Rosner, R. and Seehafer, Norbert}, title = {Magnetic helicity in space and laboratory plasmas: Editorial summary}, year = {1999}, language = {en} }