Time evolution of an ideal magnetic field with a non-zero magnetic helicity
The MHD simulation is done for a viscous fluid and an ideal magnetic field (i.e. no magnetic diffusivity). As magnetic helicity is conserved in the absence of magnetic diffusivity and is non-zero in value, it will limit the lowest level the magnetic energy can decay towards (topological constraint). Since the total energy of the turbulent MHD system is not conserved due to viscosity, the energy of the turbulent flow will be completely dissipated, leaving a remanent magnetic field with a nontrivial spatial density.
[video and simulation done by Paul Bowen, as part of his undergraduate dissertation project, 2016]
The variation of the gyrokinetic drift velocity along the unperturbed field lines
The gyro-averaged drift velocity for (left) electrons and (right) ions is shown as it varies along the unperturbed field lines (z direction). The effect of the strong gyro-average is observed for the ions. The animations are done for a single point in velocity phase space.
[Diagnostics and animations by Evgeny Gorbunov 2020, using numerical simulations performed by Dr. Daniel Told with the GENE code.]
A set of pictures obtained from my work, displayed in no particular order. While the pictures are obtained through processing scientific data, and each image is related to a physical quantity or phenomena, they are selected for their overall visual appeal. A small description of each image is given, but no rigor of therms is employed.
Turbulent magnetic field
Magnetic field-lines (in yellow) tracing turbulent structures denoted by the intensity of the magnetic energy (i.e. the blue cloud - lighter colors denoting larger values of the energy). As electrically charged particles move, they generate electromagnetic fields that in turn affect the trajectories of the charged particles. To a good degree, electrons can be seen as traveling along the filed-lines, while heavier ions have a tendency to bounce off magnetic structures. The picture is obtained from direct numerical simulation of magnetohydrodynamic (MHD) plasma turbulence.
Flower petals? No, just some turbulent current sheets!
Charged particles moving inside an anisotropic magnetic field
Cross-section of vortical structures in isotropic MHD turbulence
Cross-section of current structures in isotropic MHD turbulence
Fluid velocity (in red) and the self-consistent magnetic field (in blue) in MHD turbulence
A thin iso-surface of magnetic energy
The surface overlaps cuts in the three directions of the magnetic vector field, as a way to visualized turbulence in a plasma medium. As charged particles that perceive this surface as a magnetic mirror can be seen as bouncing off it and passing only through its holes, it is easy to understand why their trapped trajectories can become so intricate.
Alinement of numerical grids with density structures
Toroidal structures in a tokamak geometry
While the figure denotes plasma density structures, these are non-physical and are obtained as a test during code development. However, non-physical does not mean non-beautiful. This image can be seen as the artistic result of scientific software.
Magnetic field intermittency in a gyrokinetic system
Real space visualization of the norm of perpendicular magnetic fluctuations. In all four panels, the same slice through the z direction is taken, the magnetic field is normalized to its respective maximal value and values less than 0.1% of the maximum are set to zero (black color). The four panels show the real space data, high-pass filtered beforehand in Fourier space (keeping smaller and smaller scales progressively from left to right). The fact that small scales are less space filling is evident by the progressive increase in the black color.