title: Unpinning of spiral waves by electrical forcing in excitable chemical media.
abstract: We present experimental observations on the electrically forced release of spiral waves pinned to unexcitable circular obstacles in the Belosov-Zhabotinsky reaction. When the applied electric current density reaches the necessary current density J(unpin), the spiral tip is detached and subsequently drifts away from the obstacle. J(unpin) is found to increase with the obstacle diameter d. The growth rate ΔJ(unpin)/Δd is much higher for obstacles larger than the free spiral core compared to that for smaller obstacles. The experimental findings are confirmed by numerical simulations using the Oregonator model. The results imply that it is more difficult to release spiral waves pinned to larger obstacles, especially when the obstacle size exceeds that of the free spiral core.
authors.affiliation: Department of Physics, Kasetsart University, 50 Phaholyothin Road, Jatujak, Bangkok 10900, Thailand.
authors.forename: Malee
authors.initials: M
authors.lastname: Sutthiopad
authors.affiliation: Department of Industrial Physics and Medical Instrumentation, King Mongkut's University of Technology North Bangkok, 1518 Pibulsongkram Road, Bangkok 10800, Thailand and Lasers and Optics Research Group, King Mongkut's University of Technology North Bangkok, 1518 Pibulsongkram Road, Bangkok 10800, Thailand.
authors.forename: Jiraporn
authors.initials: J
authors.lastname: Luengviriya
authors.affiliation: Department of Physics, Kasetsart University, 50 Phaholyothin Road, Jatujak, Bangkok 10900, Thailand.
authors.forename: Porramain
authors.initials: P
authors.lastname: Porjai
authors.affiliation: Department of Chemistry, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Boosayarat
authors.initials: B
authors.lastname: Tomapatanaget
authors.affiliation: Institute of Experimental Physics, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, D-39106 Magdeburg, Germany.
authors.forename: Stefan C
authors.initials: SC
authors.lastname: Müller
authors.affiliation: Department of Physics, Kasetsart University, 50 Phaholyothin Road, Jatujak, Bangkok 10900, Thailand.
authors.forename: Chaiya
authors.initials: C
authors.lastname: Luengviriya
mesh_terms: D003198:Computer Simulation; D004574:Electromagnetic Fields; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D009991:Oscillometry / Q000379:methods*; D012996:Solutions / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D012996:Solutions