Spectrograph: Solar Radio Burst Classifications
| Type | Characteristics | Duration | Frequency range | Associated phenomena |
|---|---|---|---|---|
| I | Short, narrow-bandwidth bursts. Usually occur in large numbers with underlying continuum. | Single burst: ~ 1 second Storm: hours - days |
80 - 200 MHz | Active regions, flares, eruptive prominences. |
| II | Slow frequency drift bursts. Usually accompanied by a (usually stronger intensity) second harmonic. | 3 - 30 minutes | Fundamental: 20 - 150 MHz | Flares, proton emission, magnetohydrodynamic shockwaves. |
| III | Fast frequency drift bursts. Can occur singularly, in groups, or storms (often with underlying continuum). Can be accompanied by a second harmonic | Single burst: 1 - 3 seconds Group: 1 - 5 minutes Storm: minutes - hours |
10 kHz - 1 GHz | Active regions, flares. |
| IV | Stationary Type IV: Broadband continuum with fine structure | Hours - days | 20 MHz - 2 GHz | Flares, proton emission. |
| IV | Moving Type IV: Broadband, slow frequency drift, smooth continuum. | 30 mins - 2 hours | 20 - 400 MHz | Eruptive prominences, magnetohydrodynamic shockwaves. |
| IV | Flare Continua: Broadband, smooth continuum. | 3 - 45 minutes | 25 - 200 MHz | Flares, proton emission. |
| V | Smooth, short-lived continuum. Follows some type III bursts. Never occur in isolation. | 1 - 3 minutes | 10 - 200 MHz | Same as type III bursts. |
Notes
In nearly all cases, drifting bursts drift from high to low frequencies.
The Frequency Range is the typical range in which the bursts appear - not their bandwidth.
The sub-types of type IV are not universally agreed upon and are thus open to debate.
