Temporal Correlation of Hard X-rays and Meter/Decimeter Radio Structures in Solar Flares

Abstract

We investigate the relative timing between hard X-ray (HXR) peaks and structures in metric and decimetric radio emissions of solar flares using data from the RHESSI and Phoenix-2 instruments. The radio events under consideration are predominantly classified as type III bursts, decimetric pulsations and patches. The RHESSI data are demodulated using special techniques appropriate for a Phoenix-2 temporal resolution of 0.1s. The absolute timing accuracy of the two instruments is found to be about 170 ms, and much better on the average. It is found that type III radio groups often coincide with enhanced HXR emission, but only a relatively small fraction ($\sim$ 20%) of the groups show close correlation on time scales $<$ 1s. If structures correlate, the HXRs precede the type III emissions in a majority of cases, and by 0.69$\pm$0.19 s on the average. Reversed drift type III bursts are also delayed, but high-frequency and harmonic emission is retarded less. The decimetric pulsations and patches (DCIM) have a larger scatter of delays, but do not have a statistically significant sign or an average different from zero. The time delay does not show a center-to-limb variation excluding simple propagation effects. The delay by scattering near the source region is suggested to be the most efficient process on the average for delaying type III radio emission.

References in corpus (2)

• Spatial analysis of solar type III events associated with narrow band spikes at metric wavelengths
• Visibility-Based Demodulation of Rhessi Light Curves

Cited by in corpus (10)

• A Review of Solar Type III Radio Bursts
• Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
• The Relationship Between Solar Radio and Hard X-ray Emission
• Large scale simulations of solar type III radio bursts: flux density, drift rate, duration and bandwidth
• Characteristics of the flare acceleration region derived from simultaneous hard X-ray and radio observations
• Type III Solar Radio Burst Source Region Splitting Due to a Quasi-Separatrix Layer
• The Low-High-Low Trend of Type III Radio Burst Starting Frequencies and Solar Flare Hard X-rays
• Gyrokinetic electron acceleration in the force-free corona with anomalous resistivity
• Astrophysics in 2005
• Bursty acceleration and 3D trajectories of electrons in a solar flare