Emissions of the sun in radio wavelengths from centimeters
to dekameters, under both quiet and disturbed conditions.
Type I. A noise storm composed of many short, narrow-band bursts
in the metric range (300 - 50 MHz).
Type II. Narrow-band emission that begins in the meter range
(300 MHz) and sweeps slowly (tens of minutes) toward deka-
meter wavelengths (10 MHz). Type II emissions occur in
loose association with major FLAREs and are indicative of
a shock wave moving through the solar atmosphere.
Type III. Narrow-band bursts that sweep rapidly (seconds) from
decimeter to dekameter wavelengths (500 - 0.5 MHz). They
often occur in groups and are an occasional feature of complex
solar ACTIVE REGIONs.
Type IV. A smooth continuum of broad-band bursts primarily in the
meter range (300 - 30 MHz). These bursts are associated with
some major flare events beginning 10 to 20 minutes after the
flare maximum, and can last for hours.