Solar prominence

Question

I'm preparing for an upcoming school speech about solar flares and am wondering whether or not the "loop" in the following video is an example of "solar prominence" and what will eventually result in a sun eruption (and therefore coronal mass ejection) or not?

http://youtu.be/HFT7ATLQQx8?t=69

I'm not sure because it looks quite a bit different than in other videos.

And another question: is the aurora borealis the result of regular solar wind emission, or caused by coronal mass ejections? I'm wondering because I read that solar wind can bypass the earths magnetosphere (as it is non-magnetic) while Coronal mass ejections usually can't, but I read and heard both!

Answer 1

I'm preparing for an upcoming school speech about solar flares and am wondering whether or not the "loop" in the following video is an example of "solar prominence" and what will eventually result in a sun eruption (and therefore coronal mass ejection) or not?

Be careful to to state that not all prominences erupt (i.e., some fall back to the solar surface) and not all coronal mass ejections (CMEs) result from prominences.

It is also worth noting that solar flares and CMEs are actually completely different phenomena. A solar flare is really just a highly localized (spatially and temporally) enhancement in x-rays and UV light while CMEs involve an eruption of plasma from the solar surface (well, technically the ones that leave are called interplanetary coronal mass ejections or ICMEs). The processes that cause solar flares can result in energetic particles streaming out from the sun, one type of what are known as solar energetic particles (SEPs). The faster ICMEs can create magnetized shock waves which can accelerate charged particles to very high energies and also produce SEPs.

is the aurora borealis the result of regular solar wind emission, or caused by coronal mass ejections?

The aurora can be generated by both regular solar wind flow and ICMEs. In fact, the aurora is nearly always present it just sits at different latitudes and is present in different wavelengths (e.g., sometimes visible light and sometimes UV light).

Typically, ICMEs can generate much stronger aurora because they can disturb Earth's magnetosphere. The particles that precipitate into the atmosphere to interact with nitrogen and oxygen to form the visible light aurora actually come from the geomagnetic tail, not the solar wind. This occurs through several steps but the basic idea is the following. The magnetic tail stretches and snaps causing an earthward injection of energetic particles that excite electromagnetic waves (e.g., whistler waves in the form of chorus and hiss... Note I do not mean lightning-generated whistlers as the wiki article suggests, just an electromagnetic wave with similar properties [it's actually a rather generic name now but used to be extremely specific].). Some of these electromagnetic waves can strongly interact with the injected electrons and protons and cause them to stream along Earth's magnetic field into the atmosphere where they interact with and excite the neutral gas. The result is the brilliant emission of green and red light.

I'm wondering because I read that solar wind can bypass the earths magnetosphere (as it is non-magnetic) while Coronal mass ejections usually can't, but I read and heard both!

The solar wind is a magnetized plasma. It tends to flow around the Earth because Earth has an intrinsic magnetic field that deflects it. ICMEs are very large and tend to completely engulf the Earth and its magnetosphere. But the plasma within rarely enters the magnetosphere directly so it too is deflected. The primary difference is that ICMEs tend to cause much greater disturbances to the terrestrial magnetosphere which can lead to much stronger auroral displays.

Additional Relevant Answers

• Notes on the solar wind's influence on planets: https://physics.stackexchange.com/a/214509/59023
• Notes on the role electromagnetic waves play in aurora: https://physics.stackexchange.com/a/142922/59023
• Notes on charged particle motion in magnetic fields: https://physics.stackexchange.com/a/239769/59023
• Notes on cosmic ray deflection: https://physics.stackexchange.com/a/214858/59023
• Notes on solar flares: https://physics.stackexchange.com/a/258093/59023
• Notes about the north and south aurora: https://physics.stackexchange.com/a/261060/59023
• Notes about magnetic fields within ICMEs: https://physics.stackexchange.com/a/182972/59023
• Potential hazards of strong ICMEs: https://physics.stackexchange.com/a/149199/59023

Answer 2

I can't give you a better answer than is on Solar Prominences and CMEs Wikipedia.

A prominence is a large, bright, gaseous feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona. While the corona consists of extremely hot ionized gases, known as plasma, which do not emit much visible light, prominences contain much cooler plasma, similar in composition to that of the chromosphere. The prominence plasma is typically a hundred times cooler and denser than the coronal plasma. A prominence forms over timescales of about a day and may persist in the corona for several weeks or months, looping hundreds of thousands of miles into space. Some prominences break apart and may then give rise to coronal mass ejections. Scientists are currently researching how and why prominences are formed.

The red-glowing looped material is plasma, a hot gas composed of electrically charged hydrogen and helium. The prominence plasma flows along a tangled and twisted structure of magnetic fields generated by the sun’s internal dynamo. An erupting prominence occurs when such a structure becomes unstable and bursts outward, releasing the plasma.

Source: Solar Prominence, original here

As far as the solar wind is concerned:

And another question: is the Aurora Borealis the result of regular solar wind emission, or caused by coronal mass ejections? I'm wondering because I read that solar wind can bypass the earths magnetosphere (as it is non-magnetic) while Coronal mass ejections usually can't, but I read and heard both!

Coronal mass ejections might or might not affect us, it depends on which way they are aimed. The solar wind is composed of charged particles , and that's why it can interact with Earth's magnetic field. Reading all 3 links on this page will explain better than I can.

The Aurora Borealis (and the south pole version) is caused by the solar wind and again, the concise explanation is given by Wikipedia:

Aurora Wikipedia

Auroras are produced when the magnetosphere is sufficiently disturbed by the solar wind that the trajectories of charged particles in both solar wind and magnetospheric plasma, mainly in the form of electrons and protons, precipitate them into the upper atmosphere (thermosphere/exosphere), where their energy is lost. The resulting ionization and excitation of atmospheric constituents emits light of varying colour and complexity.