Solar, Space, and Geomagnetic Weather

Stephanie Osborne explains,

[This is a basic image of the Sun, complete with sunspots. The small black circle in the top right edge of the solar disk is actually Venus beginning a “transit” (passage) between us and the Sun.]

All three — solar weather, space weather, and geomagnetic weather — are interconnected. This is because the Sun has a magnetic field that extends far past the Earth, and so the Earth’s magnetic field interacts with it. “Space Weather” is essentially a term for the conditions of space in the general vicinity of Earth, but not necessarily inside the Earth’s magnetic field.

We are also sitting inside the atmosphere of the Sun, the corona. The corona is a plasma — a gas composed of charged particles, mostly protons and electrons, with some neutrons and assorted atomic nuclei (such as alpha particles — helium nuclei) thrown in for good measure. Its temperature is around a 1,400,000°-1,600,000°Kelvin, or about 2,500,000-2,900,000°F. It has a density that ranges about 5-10 particles per cubic centimeter, and it is generally moving away from the Sun, “evaporating” under the influence of the powerful solar magnetic fields.

This generates a kind of wind, usually coming out from the Sun and spiraling away — yeah, the “solar wind.” Granted, the corona isn’t very dense, but it’s dense enough to create some effects, and we’re working on using it to our benefit, like in solar sails and such, which can use the solar wind as much as light pressure to maneuver around the Solar System like a spaceborne version of the clipper ships of old. (But that’s a different blog post.) Solar wind speeds range from 400-750km/s (895,000-1,700,000mph), and under certain conditions, can get much, much faster.

...The solar magnetic field can look like this:


Now, see all those places where the magnetic field lines are going off into space, instead of looping back around to the “surface”? Those are shooting all that plasma off into space, ALONG THOSE LINES, and the result, when you look at it with the right frequency light and equipment, is what’s called a coronal hole. Looking at ‘em the right way, it looks like this:

Read more here.