| Go to the Department of Scientific Computing home page |
| Go to the IRF-U Physics in Space home page |
The below pictures and animations illustrate various results from Vlasov simulations.
The first example is the decay of an almost electrostatic, longitudal upper hybrid wave into a range of electrostatic and electromagnetic waves, such as ion and electron X waves and elecron Bernstein waves.
In order to visualise the result, the longitudal component of the eletric field is Fourier transformed in space and time. The time window is moved in time, so that one can see the temporal evolution of the frequency spectrum.
The upper hybrid wave, with a wave number of 0.05 inverse Debye lengths was ramped up at the upper hybrid frequency during a time of 600 inverse plasma frequencies, and then the pump was removed. This wave can clearly be seen in the left-hand picture below. The two first pictures below shows the high-frequency part of the spectrum, around the upper hybrid frequency.
The horisontal axis is the wave number k axis, and the vertical axis is the angular frequency omega axis.
Click on any of the below pictures to see an MPEG animation.
|
|
|
The next two first pictures shows the low-frequency part of the spectrum, around the lower hybrid frequency. Clearly, there is a coupling between the high-frequency components of the spectrum illustrated above, and the low-frequency components illustrated below.
Click on any of the below pictures to see an MPEG animation.
|
|
The next picture shows the low- and high-frequency parts of the spectrum, simultanuously.
Click on the below pictures to see an MPEG animation.
|
The next pictures show, respectively, the envelope of the longitudal electric field which was used to create the above animations, the relative ion density fluctuations, and the magnetic field fluctuations. Interestingly, there is a solitary wave with a high-amplitude electric field created, and static structures in the ion density and magnetic field.
The horisontal axis is the spatial x axis and the vertical axis is the time t axis.
|
|
|
Click on the below pictures to see an MPEG animation.
|
The next pictures show an electrostatic, one-dimensional Vlasov simulation of Bernstein-Green-Kruskal (BGK) waves.
Click on the below pictures to see an MPEG animation.
|
|