Abstract:
We recently investigated some of the hitherto unreported observational characteristics of the low
frequency (85–35 MHz) type III–V bursts from the Sun using radio spectropolarimeter observations. The
quantitative estimates of the velocities of the electron streams associated with the above two types of bursts
indicate that they are in the range
0
.
13
c
–0
.
02
c
for the type V bursts, and nearly constant (
≈
0
.
4
c
)forthe
type III bursts. We also find that the degree of circular polarization of the type V bursts vary gradually with
frequency/heliocentric distance as compared to the relatively steeper variation exhibited by the preceding type
III bursts. These imply that the longer duration of the type V bursts at any given frequency (as compared to
the preceding type III bursts) which is its defining feature, is due to the combined effect of the lower velocities
of the electron streams that generate type V bursts, spread in the velocity spectrum, and the curvature of the
magnetic field lines along which they travel.
