Recovering 3D Magnetic Turbulence from a Single Polarization Map

An observer-ready statistic that recovers inertial-range slopes and cleanly separates emission- vs. Faraday-screen structure using one map at one wavelength.

Aliaksandr (Alex) Melnichenka · Berea College Physics & CS · minor in Math Focus: MHD turbulence · astro/plasma computation
Watch the UK SPS talk (10 min) Preprint (arXiv) Slides (PDF) Code & reproducible figures

Talk recording (University of Kentucky SPS · Oct 9, 2025)

If the embed doesn’t load, open on YouTube.

What’s new

  • Directional correlation of polarization angle (operate on cos 2χ, sin 2χ) recovers turbulence slopes from a single band and avoids angle unwrapping; robust to interferometric high-pass filtering.
  • Crossover criterion (set by λ² and RM dispersion) tells you when spectra trace synchrotron angles vs. screen fluctuations (neB∥).
  • Validation on synthetic Faraday screens and Athena MHD cubes spanning sub- and super-Alfvénic regimes; measured slopes match ground-truth spectra across seeds.
  • Observer recipe: measure slopes, locate crossover, apply immediately to LOFAR/MeerKAT/VLA archives; groundwork for SKA when spectral coverage is sparse.

Takeaway for observers

With one map at one wavelength, you can already estimate inertial-range slopes and separate emission vs. screen structure—no RM synthesis required.

Reproducibility

  1. Clone repo: git clone https://github.com/astrosander/AstroTurbulence.git
  2. Create env & run: bash reproduce.sh
  3. Figures regenerate from tag 1.0.0 (commit 8731234).

Includes synthetic samples, parameter file, and a minimal notebook to apply the estimator to your map.

Artifacts

Directional spectrum recovering inertial-range slope; crossover marked where λ²·σ_RM ~ 1

Figure: Directional spectrum from a single-band polarization map. At shorter λ the slope follows the synchrotron angle field; at longer λ it follows screen fluctuations. The data-driven crossover agrees with predicted scaling.

Publication status

  • Working title: Recovering 3D Magnetic Turbulence from Single-Frequency Faraday Screens
  • Authors: A. Melnichenka (first author), A. Lazarian, D. Pogosyan
  • Status: manuscript in preparation; preprint targeted before AAS (Jan 2026).

Talks & media

  • UK SPS Invited Talk (Oct 9, 2025) — video above
  • APS DPP 2025 (Virtual session) — contributed oral, Nov 19, 2025
  • AAS #247 (Jan 4–8, 2026) — abstract planned
  • Lazarian Conference (Nov 2–7, 2025) — related turbulence work

About the author

Belarusian student at Berea College (KY), double major in Physics & Computer Science; national Physics Olympiad medalist and Presidential Award laureate. Research threads: MHD turbulence diagnostics; self-interacting dark matter (local MC/Langevin); electron-fluid instabilities.

Verification & links