The Influence Of Electric Fields On The Drift Of Scroll Waves In Excitable Media

Spiral waves,as an important wave pattern,exist in numerous systems,including chemical,physical and biological systems.The center of the spiral wave is a phase singularity with spiral wave rotating around it.Scroll waves,which are extensions of two-dimensional spiral waves in the third dimension,also exist in many systems.The scroll wave,whose structure and dynamical motion are more complex than spiral wave's,rotates around one-dimensional phase singularity called its filament.The filament of the scroll wave can be straight,curved,or even more closed into a circular hoop,known as a scroll ring.Spiral waves and scroll waves have been shown to underlie certain types of cardiac arrhythmias,such as ventricular tachycardia and fibrillation,the main cause of sudden cardiac death.Therefore,it attracts the great attention of people to study the spiral and scroll waves.This thesis studies the drift of the spiral and scroll waves in the electric field by the numerical simulation using Barkley model.The spiral wave drifts along a straight line in the presence of an ac electric field whose frequency is twice the spiral wave's frequency.The thesis studies the drift of the spiral when the frequency of an ac electric field is around twice that of the spiral wave.We found that the spiral wave drifts along an arc when the frequency of an ac electric field is slightly much or less twice that of the spiral wave,and the more far away,the smaller the radius is.So we can know more about the drift of the spiral due to the electric field.What's more,the thesis also studies the drift of the scroll wave whose filament is straight under the electric field.Last we also study the drift of the scroll wave whose filament is a ring under a dc electric field and the drift of the scroll wave with different initial phase under the ac electric field with different frequency.