Computational Astrophysics Research
Developing novel diagnostic techniques for magnetohydrodynamic turbulence and advancing galaxy evolution modeling through large-scale cosmological simulations.
Research focus:
MHD Turbulence & Galaxy Evolution
Collaboration:
UW-Madison & MIT Kavli
Publication:
ApJ Letters 2025 (In Review)
Active Research Projects
Faraday-Screen Turbulence Diagnostics
Angular correlation functions for LOFAR rotation measures reveal Kolmogorov-type cascades.
High-Resolution Turbulence Simulations
Advanced 512³ spectrum generation implementing Kolmogorov theory with time-invariant design and random FFT phases. This sophisticated approach ensures statistical isotropy while maintaining proper energy cascade characteristics.
Mathematical Framework
Spherical Coordinate Transformation
Velocity increment decomposition in spherical coordinates with azimuthal averaging for isotropic turbulence analysis.
Angular Statistics Analysis
Single and two-point PDFs for polar angles, vector azimuth, and Stokes azimuth showing theoretical validation.
Structure Function Analysis
3D Polar Angle
R^(2/3) scaling
Vector Azimuth
R^(2/3) scaling
Stokes Azimuth
R^(5/3) scaling
2D Simulation Validation
Stokes Parameter Analysis
512² 2D simulation showing excellent correlation with R^(5/3) dependence.
Velocity Field Validation
Distribution analysis confirming homogeneity with no directional preference in the turbulent velocity field.
Research Visualization
Publications
Turing instability and electronic self-oscillatory dynamics in Dirac fluids
Authors: Prayoga Liong, Aliaksandr Melnichenka, Anton Bukhtatyi, Albert Bilous, Leonid Levitov
Publication date: 2025/12/18
Journal: arXiv preprint arXiv:2512.16571
Viscous films flowing down an incline can form self-sustained running waves, known as Kapitsa roll waves. Here we describe an analogous electron-hydrodynamic instability that produces similar running waves in Dirac materials such as graphene mono- and multilayers. It arises when carrier kinetics near charge neutrality make current dissipation strongly density-dependent. As the flow velocity exceeds a critical value, the system transitions to a state with coupled spatial and temporal oscillations. Experimentally, the instability should manifest as (i) a nonanalytic behavior characteristic of a second-order transition--an abrupt increase in time-averaged current--and (ii) narrow-band emission at the characteristic ``washboard'' frequency, where is the modulation wavelength. This behavior parallels the AC and DC transport of sliding charge-density waves, but here it originates from a distinct, intrinsic mechanism unrelated to disorder. Estimates indicate that the emission frequency, tunable by current, spans a broad range, highlighting Dirac bands as a promising platform for high-frequency electron-fluid dynamics.
Undergraduate-Led High-Resolution MHD Validation of Lazarian–Pogosyan Faraday Turbulence Theory
Authors: Aliaksandr Melnichenka, Alex Lazarian, Dmitri Pogosyan
Publication date: 2025/11/18
Conference: American Physical Society DPP 2025
Leveraging a fully in-house pipeline I created, I carry out the first high-resolution, parameter-controlled simulation campaign that quantitatively stress-tests the Lazarian & Pogosyan 2016 (LP16) analytic model for Faraday-rotated synchrotron turbulence. Compressible, sub- to trans-Alfvénic MHD cubes up to 512³ are ray-traced to generate Stokes Q,U mosaics across 0.1–2 m. From them I extract the complex correlator 〈P P*〉, the angle-structure function Dφ(R, λ), and the saturation scale Rsat(λ). The study unambiguously verifies the three cornerstone LP16 scalings: λ⁴ damping of correlations, Kolmogorov inertial-range slope Dφ ∝ R5/3, and the π²/6 plateau with Rsat ∝ λ4/3. I further provide a resolved lookup grid that observers can apply directly to LOFAR, MWA and early SKA data, effectively bridging theory, simulation and observation. All coding, analysis and visualisation were executed by me as an undergraduate researcher.