Millisecond microwave spikes at 8 GHz during solar flares

Highly circularly polarized spikes have been observed during solar flares up to 8 GHz. The typical half-power bandwidth was 120 MHz, and the duration was less than the time resolution of 100 ms. A group of 46 spikes in the 6.5 - 8.0 GHz range has been observed at the maximum of an H-alpha flare and within 3 s of the peak of microwave emission observed at 2.7 GHz by other observatories. The peak flux of the spikes reached 60 sfu above background. These emissions closely resemble the spikes previously reported at lower frequency. If interpreted as second harmonic of the electron gyrofrequency, a magnetic field exceeding 1400 G would be requested in the corona.