Type III Solar Burst

Rapidly drift from high to low frequencies. May exhibit harmonics.
Often accompany the flash phase of large flares.

The chart above was taken from the Winward Community College Jupiter Observatory receiver at 20.1 mHz on September 20, 2000. The times are local Hawaiian time so add 10 hours for UT. The burst is believed to be about 18 dB above the galactic background.

Type II Solar Burst

Slow drift from  high to slow frequencies.

The stripchart above was captured at the new Jupiter Observatory at Windward Community College on the Island of Oahu in Hawaii on July 28, 2000. The receiver is one of Dick Flagg's Jove Receivers attached to the standard in-phase version of the dual dipole Jove antenna. Primary beam pattern is to the zenith. The frequency is approximately 20.1 Mhz.

Solar Burst on Skypipe

Solar Bursts can always be detected at the frequency about 20 MHz. The common characteristic is turn on rapidly and decay slowly.

Here is the examples received by from NASA’s Radio JOVE Project.

But, actually, the solar burst can be classified into 5 kinds.

Type I  Short, narrow band events that usually occur in great numbers
together with a broader band continuum. May last for hours or days.


Type II  Slow drift from high to low frequencies. Often show fundamental
and second harmonic frequency structure.


Type III  Rapidly drift from high to low frequencies. May exhibit harmonics.
Often accompany the flash phase of large flares.


Type IV  Flare-related broad-band continua.


Type V  Broad-band continua which may appear with III bursts. Last 1 to 2
minutes, with duration increasing as frequency decreases.

Solar Burst

Solar Burst stands for all the burst happened on the surface of the Sun, such as Sunspots and Solar Flares.

Because of the varying rotational speed of the Sun, there are some regions with intense localized magnetic lines which named Sunspots. As the Sun is a gas ball, the rotate speed on the equator seems faster than the speed on the poles. Therefore, the magnetic field lines are dragged together and twisted which always run independently from pole to pole. The flux lines pushed by hot gases break through to the Sun’s surface. And the distorted field lines slows down rising convection currents, which causing the region to cool. The dark spots in the bottom video are the cooler areas comparing to the hotter surroundings.

from http://sdo.gsfc.nasa.gov/data/

The Solar Flare is defined as a sudden burst on the surface of the Sun. (John D. Kraus, 1986) Most flares appear in solar active regions, for instance, near the sunspots, where the magnetic field lines on the surface of the Sun beyond the corona. The energy for solar flare mainly comes from the magnetic energy released by corona. During the solar flare appearing, there is a sudden increase in brightness can be observed, the flux of radio waves, ultraviolet and X-ray will soar and sometimes high-energy γ-ray or charged particles will be emitted too.

Radio Telescope

As a very fast development in Radio astronomy, a subfield of astronomy which studies celestial objects at radio frequencies, radio telescope was invented in a form on directional radio antenna.

In their astronomical role they differ from optical telescopes in that they operate in the radio frequency portion of the electromagnetic spectrum where they can detect and collect data on radio sources.

In 1931, Karl Guthe Jansky, an engineer with Bell Telephone Laboratories, built the first radio antenna which can identify an astronomical radio source. This kind of telescope is basically a very sensitive radio receiver.

Comparing to the communication receivers which are used to extract information and have been intentionally modulated onto the radio wave, radio telescope receivers are designed to measure the intensity of the radio wave over some limited band of frequencies. Therefore, the radio telescope can be seen as an energy measuring device.

The two figures above show the whole system of simple radio telescope. And this is also the system our group used to detect the space.