TODAYS TOPIC-WHAT IS A SOLAR PROMINENCE? This is the non-physicist, layman’s version. It’s crisp winter day and you are patiently finishing up your last load of laundry in the dryer. The buzzer sounds and you open the door to retrieve your socks and towels. All of the sudden…shock!, pow! Pop! Shock! POW!, you are electrocuted several times by the static electricity built up in your laundry. You also notice how all of your socks are clinging to your towels by some imaginary force and when you pull them apart…SHOCK! POW! ZAP! PING!. You get zapped again! What is all this about? Well, welcome to the electromagnetic force my friends. This is exactly the same force and relationship that causes almost every observable solar phenomenon from solar prominences to spicules to solar fares and CME’s. A little basic electricity if you will.; Electricity is simply the transference of electrons from one place to the other. Electrons always try to release their energy f they can so electricity always travels from a high charge to a lower charge (- to +) . Electricity is generated whenever two objects with magnetic fields come in close proximity of each other. Since everything has a magnetic field, electricity and the electromagnetic force is everywhere, all the time. Your laundry rolling around in the dryer causes repeated and close interaction between the magnetic fields of various pieces of clothing that already have a magnetic field and it also accentuates the magnetic field by the application of heat (increasing the movement of atoms). The Sun is a massive churning dynamo of extremely hot and highly charged Hydrogen and Helium gas or plasma (with a little bit of trace elements added like Calcium and Oxygen). Since the Sun is not a solid, its rotation is manifested at different speeds based on the latitude at which it is observed, faster at the equator and slower at the poles. The Sun also has several distinct layers of densities from the super-dense core out through the convective zone to the photosphere, chromosphere, Corona, etc… As these different charges and temperature layers interact under extreme temperatures and differential speeds, the Sun becomes a gigantic version of the load of socks and towels in your dryer. I’m not making this stuff up folks, this is why science is so cool…☺ A solar prominence/filament is one way in which the electromagnetic fields generated by the solar “dynamo” are manifested in the Sun’s chromosphere. When magnetic field lines get into close proximity to each other in the chromosphere, sometimes they are broken apart and reconnect with each other in an explosive manner(solar flare). Sometimes they simply join their forces together and produce a relatively stable field line or path of enormous strength on which plasma and gas of various atoms travels along for hours of weeks depending on the charge and stability. These are called prominences when they are viewed on the edge of the solar disk and filaments when they are viewed with the solar disk as a background. Solar Prominences are bright on the edge of the disk as they are much hotter than their background (space) and they appear darker than the surrounding surface when viewed on the disk because they are cooler than the surface when held aloft. Sometimes the magnetic field lines simply disconnect from their roots on the surface and are extended out into space trying to find some favorable place to reconnect. Some other times the entire field line is just expelled from the disk completely and we call these detached prominences. Detached Prominences can hover above the surface for days or explode out into the Corona in an instant. Solar prominences are best viewed in a Hydrogen Alpha telescope like those seen on this forum. Solar prominences can also be viewed with a Calcium K telescope although their structures are usually slightly different. Since the CaK line shows much higher energy (shorter wavelength) events you can sometimes see prominences far longer our more extended than in H-Alpha. It takes practice but they are viewable in CaK also. The below images show what I believe to be the longest prominence ever recorded from Earth or space. It was captured on Aug 31st at Dragon*Con in Atlanta by me and an 8 year old girl who was watching it with me at an outreach event. I could move my telescopes to get the entire thing so I believe I beat out even NASA satellites with this one’s length. It extended for over 800,000 miles into the Sun’s Corona. This would take a towel or sock about a million miles long to create in your dryer…☺ The first photo shows the H-Alpha filament in the lower left that exploded creating this event. The 2nd photo shows the remnants on the surface, notice the two solar tsunamis going away from the blast site. The third image shows the H-ALpha view of the initial eruption, notice the unfolding prominence on the lower left. The 4th mage is the Calcium K prominence at its furthest visible extension-over 800,000 miles in three distinct arms as the field line explodes out into the corona!! Remember, these magnetic field lines are traced out by the Hydrogen/Helium gas and plasma due to the electromagnetic force and produce some of the most intricate structures in nature. The Sun almost always has some sort of prominence activity whether solar maximum or not. And it is ALWAYS beautiful to watch the changes over time through your narrowband H-Alpha telescopes. The last image is the solar dynamo and how it extends magnetic field lines outward into space.
Posted on: Sun, 04 Aug 2013 14:25:07 +0000
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