# A fast radio burst cyclone in technicolour: evidence of plasma lensing

**Authors:** Pavan A. Uttarkar, Ryan M. Shannon, Kelly Gourdji, Adam T. Deller, Pravir Kumar, Navin Sridhar, Marcus E. Lower, Artem Tuntsov, Atharva D. Kulkarni, Simon C. -C. Ho, Yuanming Wang, Joscha N. Jahns-Schindler  
**arXiv:** [2602.16409](https://arxiv.org/abs/2602.16409)  
**Date:** 2026-02-16  
**Summary page:** https://www.summarizepaper.com/en/paper/2602.16409v1/

## Key points

- Fast radio bursts (FRBs) are bright, energetic, radio pulses from beyond our galaxy.
- Some FRB sources produce repeat bursts while others do not.
- FRB 20240114A is the most active repeating source to date with 5526 repetitions detected.
- The bursts exhibited extreme spectral and temporal variability, suggesting magnification by foreground plasma lenses.
- Plasma lenses play a significant role in shaping burst emission characteristics across the entire FRB population.
- An Extended Source Effect (ESE) model was proposed to explain burst storms B4 and B5 observed during the study.

## Summary

Fast radio bursts (FRBs) are bright, energetic, radio pulses originating from beyond our galaxy. A distinct division has been observed within the FRB population: some sources produce repeat bursts, while the majority do not. Among the repeating sources, rare repetitions have been documented, but none have been extensively studied across wide bandwidths to unravel the underlying physical processes responsible for the emission variations caused by intervening ionised gas. In a recent study, radio observations of FRB 20240114A, the most active repeating source to date, were conducted using an ultrawideband receiving system. Remarkably, 5526 repetitions were detected, unveiling extreme spectral and temporal variability in burst emission. The bursts exhibited long-term broadband variations in central emission frequency over several months and narrowband bursts with correlations in central frequencies on timescales ranging from milliseconds to minutes. These spectral and temporal properties suggest that the source may be undergoing magnification by foreground plasma lenses potentially embedded in a turbulent circumsource medium. This exceptional example underscores the significant role of plasma lenses in shaping burst emission characteristics and offers insights into explaining the diverse activity levels and energetics observed across the entire FRB population. Furthermore, an Extended Source Effect (ESE) model was proposed to explain burst storms B4 and B5 observed during the study. The model utilized two Gaussian lenses to simulate plasma density variations and demonstrated how refracted waves due to these lenses could cause apparent changes in source brightness. Overall, this comprehensive investigation sheds light on the complex dynamics at play in FRB emissions and highlights the importance of considering plasma lensing effects when interpreting burst properties.