Solar Flare Precursors are Electric! But What About Venus?

'Sigmoids' are S-shaped structures found in the outer atmosphere of the Sun (the corona), seen with X-ray telescopes and thought to be a crucial part of explosive events like solar flares. Now a group of astronomers have developed the first model to reproduce and explain the nature of the different stages of a sigmoid’s life.

Recently, the X-Ray Telescope (XRT) on board the Hinode space mission was used to obtain the first images of the formation and eruption phase of a sigmoid at high resolution. These observations revealed that the structure of the sigmoid is complex: it consists of many, differently oriented, loops that all together form two opposite J-like bundles or an overall S-shape. They also showed that at the end of its life the sigmoid produces a 'flare' eruption.

The new model describes how sigmoids consist of many thin and twisted layers (or ribbons) of strong electric current. When these layers interact it leads to the formation of the observed powerful flares and the eruption of strong magnetic fields which carry highly energetic particles into interplanetary space. The team also found that as the sigmoids die out, they produce a ‘flare’ eruption.

“Sigmoids work as ‘mangers’ or ‘cocoons’ for solar eruptions. There is a high probability that they will result in powerful eruptions and other explosive events. Our model helps scientists understand how this happens.”

...we are still not able to explain why the global atmospheric circulation of the planet results in a double and not single vortex formation at the poles.

Venus Express science team members say they want to know how these vortices remain stable and where they get their energy. This goes to the heart of what drives the super-rotating upper atmosphere of Venus. So I repeat and expand here some of the closing comments from my Feb 5, 2005 article.

Venus, as shown by its cometary magnetosphere (plasmasphere), is still discharging strongly to the solar plasma. The enhanced infrared emission seen from the polar dipole is due to the dissipation of electrical energy in the upper atmosphere of Venus. The polar dipole has a variable rotation rate and it varies the position of its axis of rotation with respect to that of the planet. It was observed to move 500 km from the Venusian pole in less than a day and return just as quickly. The variable nature of the electrical input to Venus via the Sun and the snaking about of the Birkeland currents explain both these characteristics.

Of particular interest are the linear filaments sometimes seen connecting the opposite sides of the hot spots. Taylor writes: "It is virtually impossible, even with complete license, to begin to speculate in any detail as to what mechanism could give rise to such a curious effect." The answer, in the Electric Universe model is simple. They are a feature seen in simulations of the behavior between two converging Birkeland current filaments where plasma becomes trapped in the elliptical core between them.