Skip to main content

What is SOLAR WIND ?

 

SOLAR WIND

The solar wind continuously flows outward from the Sun and consists mainly of protons and electrons in a state known as a plasma. Solar magnetic field is embedded in the plasma and flows outward with the solar wind.

Different regions on the Sun produce solar wind of different speeds and densities. Coronal holes produce solar wind of high speed, ranging from 500 to 800 kilometers per second. The north and south poles of the Sun have large, persistent coronal holes, so high latitudes are filled with fast solar wind. In the equatorial plane, where the Earth and the other planets orbit, the most common state of the solar wind is the slow speed wind, with speeds of about 400 kilometers per second. This portion of the solar wind forms the equatorial current sheet.

During quiet periods, the current sheet can be nearly flat. As solar activity increases, the solar surface fills with active regions, coronal holes, and other complex structures, which modify the solar wind and current sheet. Because the Sun rotates every 27 days, the solar wind becomes a complex spiral of high and low speeds and high and low densities that looks like the skirt of a twirling ballerina (see figure). When high speed solar overtakes slow speed wind, it creates something known as a corotating interaction region. These interaction regions consist of solar wind with very high densities and strong magnetic fields

Above the current sheet, the higher speed solar wind typically has a dominant magnetic polarity in one direction and below the current sheet, the polarity is in the opposite direction. As the Earth moves through this evolving ballerina skirt, it is sometimes within the heliospheric current sheet, sometimes above it and sometime below it. When the magnetic field of the solar wind switches polarity, it is a strong indication that Earth has crossed the current sheet. The location of the Earth with respect to the current sheet is important because space weather impacts are highly dependent on the solar wind speed, the solar wind density, and the direction of the magnetic field embedded in the solar wind.

Each of the elements mentioned above play a role in space weather. High speed winds bring geomagnetic storms while slow speed winds bring calm space weather. Corotating interaction regions and to a lesser extent, current sheet crossings, can also cause geomagnetic disturbances. Thus specifying and forecasting the solar wind is critical to developing forecasts of space weather and its impacts at Earth.

Comments

Post a Comment

Popular posts from this blog

Build a Bubble-Powered Rocket!

  Build a Bubble-Powered Rocket! Build your own rocket using paper and fizzing tablets! Watch it lift off. How high does your rocket go? Print this page for the instructions. Suggestion: Find a grown-up to do this activity with you. Materials: Paper, regular 8-1/2- by 11-inch paper, such as computer printer paper or even notebook paper. Plastic 35-mm film canister (see hints below) Cellophane tape Scissors Effervescing (fizzing) antacid tablet (the kind used to settle an upset stomach) Paper towels Water Eye protection (like eye glasses, sun glasses, or safety glasses) Hints: The film canister MUST be one with a cap that fits INSIDE the rim instead of over the outside of the rim. Sometimes photography shops have extras of these and will be happy to donate some for such a worthy cause. Keep in mind: Just like with real rockets, the less your rocket weighs and the less air resistance (drag) it has, the higher it will go. Making the Rocket You must first decide how to cut your paper. ...
Post a Comment
Read more

Make a topographic map!

  Make a topographic map! Build your own mountain and make a topo map of it! A topographic map, or "topo map," is a way to show mountains and valleys on a flat piece of paper. Topo maps are handy and necessary for many uses, including building roads and hiking trails in the mountains. The map shows where the hills and valleys are and how steep they are. What you need: A lump of clay or Play-Doh® about the size of a coffee mug.  Piece of cardboard or large tile on which to work the clay Piece of dental floss, about 2 feet (around 60 centimeters) long Ruler Piece of plain, white paper Long pencil 2 toothpicks What to do: Put the lump of clay on the cardboard and shape a mountain about 4 inches high. Making the map is more fun if you make your mountain a little lop-sided or oddly shaped. However, the mountain should be flat on the bottom. Use the long pencil to poke two holes straight down through the center of the mountain. Make sure your two holes go all the way through the mo...
Post a Comment
Read more

How Scary Is Space?

How Scary Is Space? Get Ready for Galactic Goosebumps! In a scary Halloween movie, monsters, ghouls, and haunted houses can give you the creeps! Those things are, of course, just stories that were made up to give you a fright. If you want a real scare, check out these nine unearthly nightmares that could be happening right now in our own galaxy. Eek! Miranda the Monster Moon Miranda is an icy moon of Uranus, the seventh planet from our Sun. If you look closely at Miranda, you’ll notice a mismatched appearance. Are those scars a sign that this moon was patched together like Frankenstein’s monster? Nope! Those patches are actually deep craters, high ridges, and extreme cliffs. A Frightening Face on the Sun When NASA’s Solar Dynamics Observatory captured this picture of our Sun in October 2014, it looked like the Sun was getting ready for Halloween! You can light up the face of a jack-o-lantern at home with a candle or flashlight. What’s lighting up this Sun pumpkin’s face? Active reg...
Post a Comment
Read more