Coronal Diagnostics via Modeling Periodic-beaded Stripes of Solar Radio Bursts

Using high-resolution data from the Chashan Broadband Solar Radio Spectrometer at meter wavelengths of the Chinese Meridian Project—Phase II, C. Li et al. identified a novel fine spectral structure of solar radio bursts, termed periodic beaded stripes, and proposed a generation mechanism. Here we report additional events and develop a quantitative method to determine the physical conditions in the emission region. Periodic stripes tend to occur in the postphase of flares and are associated with complex magnetic configurations. They repeat on subsecond timescales and show ∼0.1 s bead-like modulations, often accompanied by low-frequency absorptions. Modeling the chained stripes with linear kinetic theory of the double plasma resonance (DPR) instability constrains the source-region magnetic field to 0.2–1.7 G and the plasma density to (1–7) × 10 8 cm −3 . The former follows the drift of individual stripes, and the latter tracks the overall trend. This study summarizes the key properties of periodic beaded stripes and establishes a quantitative DPR-based framework for coronal diagnostics.