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
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
1 - 5 minutes
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.|
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.