Protection by the magnetic field

[Hazel M]

Can someone put into layman's terms exactly how the magnetic field protects us from "bombarding cosmic radiation"? Exactly what does it act upon and (I'm guessing) turn back from Earth? The magnetic part of the electromagnetic force remains a dark spot in my understanding and I suspect part of the answer is here. Only a small part, I fear.

 

 

I came up with this question while reading: http://www.sciencedaily.com/releases/2014/06/140620115751.htm?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+sciencedaily%2Ftop_news%2Ftop_science+(ScienceDaily%3A+Top+Science+News)

 

Thank you.

[lamironi]

Here is answer for your question

http://www.suntrek.org/sun-earth-connection/earth-under-attack/how-magnetic-fields-protect.shtml

[Hazel M]

Oh, thank you, lamironi! I think I got it. If/when Earth's magnetic field reverses, Solar wind's magnetic field can hook on for a ride. Solar wind is something I need to know more about but, that aside, do I have it right? In other words, here is a weakness in the planet's construction - a magnetic field that can reverse and is weak while it does so.

[Acme]

Oh, thank you, lamironi! I think I got it. If/when Earth's magnetic field reverses, Solar wind's magnetic field can hook on for a ride. Solar wind is something I need to know more about but, that aside, do I have it right? In other words, here is a weakness in the planet's construction - a magnetic field that can reverse and is weak while it does so.

Earth's magnetic field has reversed many times, and yet here we are. When it does reverse it does so in bits and stages but study suggests it does not simply disappear. Humans' biggest concern from the Sun is that large CME's (Coronal Mass Ejections) can disrupt satellites and induce electrical currents in our power grids which can overload and burn out the circuits. These CME's can occur at any Sun cycle and the Earth's magnetic field at any strength it exhibits is no shield against them.

 

New investigation shows that the Sun's magnetic field regularly link with Earth's to open 'portals' that allow the solar wind into the atmosphere where it otherwise would be redirected. >> Hidden Portals in Earth's Magnetic Field

 

While not particularly germane to your question but interesting nonetheless, the Sun's magnetic field reverses every 11 years in step with the sunspot cycle. >> Suns magnetic field about to flip

 

PS Here's a page that has explanatory articles and current satellite data and news stories on the Sun's activity. >> spaceweather.com

Edited June 22, 2014 by Acme

[Hazel M]

Thank you, Acme. I'll get to the articles tomorrow. They sound interesting. And, yes, we sometimes worry about the least of our problems. But it's so interesting, what goes on out there.

[Enthalpy]

Our atmosphere protects us from cosmic rays. The geomagnetic field rather protects the atmosphere against erosion by incoming particles.

 

Power grids may have been disrupted once many decades ago in northern America through such a process - or not. The proper answer is to build protections in. It hasn't happened again.

 

Same for satellites. Recent electronic components are more resistent, and satellite architecture shields them better. Then, you can design the circuits to survive occasional events. This worry is very largely overvalued: (1) It was serious at the beginning of space exploration (2) It permits to explain satellite failures through bad luck, not designer fault (3) This story serves as an excuse understandable by the public to study our Sun's activity (4) Meanwhile, which components are sensitive or not is known, and the consequences as well, so designers adapt.

[Acme]

Our atmosphere protects us from cosmic rays. The geomagnetic field rather protects the atmosphere against erosion by incoming particles.

Correct.

 

Power grids may have been disrupted once many decades ago in northern America through such a process - or not. The proper answer is to build protections in. It hasn't happened again.

Well, not exactly and it is some of the protections already built in that will burn out. These protections are large and expensive and because of the expense and that it is uncommon to have a lot of them blow at once there is not a large stock of them. Not only is the grid at risk, large solar storms can induce currents in other long conductors such as rail lines. (Note: I was thinking of large transformers here; see below reference.)

 

Edit: Carrington-class CME Narrowly Misses Earth [in 2012]

May 2, 2014: Last month (April 8-11), scientists, government officials, emergency planners and others converged on Boulder, Colorado, for NOAA's Space Weather Workshopan annual gathering to discuss the perils and probabilities of solar storms.

 

The current solar cycle is weaker than usual, so you might expect a correspondingly low-key meeting. On the contrary, the halls and meeting rooms were abuzz with excitement about an intense solar storm that narrowly missed Earth.

 

"If it had hit, we would still be picking up the pieces," says Daniel Baker of the University of Colorado, who presented a talk entitled The Major Solar Eruptive Event in July 2012: Defining Extreme Space Weather Scenarios.

 

The close shave happened almost two years ago. On July 23, 2012, a plasma cloud or "CME" rocketed away from the sun as fast as 3000 km/s, more than four times faster than a typical eruption. The storm tore through Earth orbit, but fortunately Earth wasn't there. Instead it hit the STEREO-A spacecraft. Researchers have been analyzing the data ever since, and they have concluded that the storm was one of the strongest in recorded history. "It might have been stronger than the Carrington Event itself," says Baker.

 

The Carrington Event of Sept. 1859 was a series of powerful CMEs that hit Earth head-on, sparking Northern Lights as far south as Tahiti. Intense geomagnetic storms caused global telegraph lines to spark, setting fire to some telegraph offices and disabling the 'Victorian Internet." A similar storm today could have a catastrophic effect on modern power grids and telecommunication networks. According to a study by the National Academy of Sciences, the total economic impact could exceed $2 trillion or 20 times greater than the costs of a Hurricane Katrina. Multi-ton transformers fried by such a storm could take years to repair and impact national security.

...

Also, a large solar storm has knocked out a power grid since the Carrington event.

March 1989 geomagnetic storm

The March 1989 geomagnetic storm was a severe geomagnetic storm that caused the collapse of Hydro-Québec's electricity transmission system. It occurred during solar cycle 22....

Same for satellites. Recent electronic components are more resistent, and satellite architecture shields them better. Then, you can design the circuits to survive occasional events. This worry is very largely overvalued: (1) It was serious at the beginning of space exploration (2) It permits to explain satellite failures through bad luck, not designer fault (3) This story serves as an excuse understandable by the public to study our Sun's activity (4) Meanwhile, which components are sensitive or not is known, and the consequences as well, so designers adapt.

Actually no. I just read a paper on this which I will try to find again, but basically because the chips are smaller they are more susceptible to charged particles. Apparently the impacts don't burn out the circuits, but they change bits and this can cause system failures. Shielding is heavy and expensive and for the highest energy particles they don't protect the chips.

 

I'll go try to find a couple references to add to this post.

 

Edit #2: This isn't the paper I read, but it will do for now. Correlation of GEO Communications Satellite

Anomalies and Space Weather Phenomena: Improved

Satellite Performance and Risk Mitigation

Edited June 23, 2014 by Acme

[Enthalpy]

About satellites: I've built my own, and more importantly, discussed with SSTL colleagues who had built a dozen and operated them for decades. The result is that

(1) Latchup doesn't happen. I had protected electronics against it, they had already suppressed their protections.

(2) Lost bits do happen from time to time. That's a good reason to have error-correcting codes, and software with internal checkings and restart capability.

 

The rest is literature, either from the time of >10µm CMOS, or by people whose job relies on circuit protection. Already 4µm CMOS was incapable of latchup. Some bits are lost, fine; this happens on Earth as well, for instance big computers must protect themselves against and do it. Once the hard and software is robust, whether more or less bits are lost during a solar event is unimportant.

 

For power lines on Earth, adequate protection is the solution. Because passive protection is better than prediction. And because we have the proper components now (SiC didn't exist in 1989, vacuum switches were rare), which let the line conductors themselves dissipate the excess energy.

 

Which doesn't prevent people to make more research on the topic and publish it. I've nothing against, but these two justifications are outdated.

[Acme]

About satellites: I've built my own, and more importantly, discussed with SSTL colleagues who had built a dozen and operated them for decades. The result is that

(1) Latchup doesn't happen. I had protected electronics against it, they had already suppressed their protections.

(2) Lost bits do happen from time to time. That's a good reason to have error-correcting codes, and software with internal checkings and restart capability.

 

The rest is literature, either from the time of >10µm CMOS, or by people whose job relies on circuit protection. Already 4µm CMOS was incapable of latchup. Some bits are lost, fine; this happens on Earth as well, for instance big computers must protect themselves against and do it. Once the hard and software is robust, whether more or less bits are lost during a solar event is unimportant.

Interesting. Do you have some references to all this that I can learn from?

 

For power lines on Earth, adequate protection is the solution. Because passive protection is better than prediction. And because we have the proper components now (SiC didn't exist in 1989, vacuum switches were rare), which let the line conductors themselves dissipate the excess energy.

 

Which doesn't prevent people to make more research on the topic and publish it. I've nothing against, but these two justifications are outdated.

Again interesting, and again do you have some references I can read and learn from?

[Mordred]

I believe I understand where Enthalphy is coming from, protection from inductive currents whether from lightning strikes or solar flares essentially boils down to adequate grounding. Where damage usually occurs is when the grounding is insufficient to handle the induced currents, either through poor design, or mechanical failure (damaged wiring etc). Electronic circuits are designed to filter out unwanted noise, part of the noise protection circuits include a path to the ground plane to remove the excess currents. Another aspect is that the power supply itself is regulated, take your PC power supply for example. The PS (power supply) is regulated as its circuit utilizes a pulse width modulation circuit. Basically what this means instead of sending a steady current at a given voltage, the PS sends on/off pulses, when more current is demanded by the PC load, the rate of pulses increases generating a higher current flow and vise versa.

 

Now at the chip gate level, ie a memory gate, each memory gate will only accept voltages within a tight limit to recognize a 1 or a 0. For example on a TTL (total transistor logic) logic circuit. the recognized voltages are 0.4-0.8 volts for a digital 0, and 4.4 to 4.8 volts for a digital 1. So any voltages outside those limits isn't recognized. Even if by sheer luck the induced currents produce those values, you also require key signals to active a chip. These signals have a specific timing with the data signal, such signals include Read or write, Chip enable, and in the case of memory RAS and CAS (row and column activation signal). If the timing is off then the chip does not change the data already stored within it

With those requirements it is highly unlikely to gain corrupted data due to induced voltages from a lightning strike or a solar flare,

the damage from lightning strikes and solar flares typically damage the components. However adequate grounding can and does offer protection. There is though interferance noise in analog signals, but again analog circuits have noise protection, though in some cases the noise is outside the protection design, this doesn't generate a latch up. Instead it generates unrecognized and corrupted data, Error correction codes can regenerate the corrupted bits from a transmission. (there is too many error correction codes to go into any length on this) checksum is one example

http://en.wikipedia.org/wiki/Checksum

Edited June 24, 2014 by Mordred

[Acme]

I believe I understand where Enthalphy is coming from,

protection from inductive currents whether from lightning strikes or solar flares essentially boils down to adequate grounding. Where damage usually occurs is when the grounding is insufficient to handle the induced currents, either through poor design, or mechanical failure (damaged wiring etc). Electronic circuits are designed to filter out unwanted noise, part of the noise protection circuits include a path to the ground plane to remove the excess currents. Another aspect is that the power supply itself is regulated, take your PC power supply for example. The PS (power supply) is regulated as its circuit utilizes a pulse width modulation circuit. Basically what this means instead of sending a steady current at a given voltage, the PS sends on/off pulses, when more current is demanded by the PC load, the rate of pulses increases generating a higher current flow and vise versa.

 

Now at the chip gate level, ie a memory gate, each memory gate will only accept voltages within a tight limit to recognize a 1 or a 0. For example on a TTL (total transistor logic) logic circuit. the recognized voltages are 0.4-0.8 volts for a digital 0, and 4.4 to 4.8 volts for a digital 1. So any voltages outside those limits isn't recognized. Even if by sheer luck the induced currents produce those values, you also require key signals to active a chip. These signals have a specific timing with the data signal, such signals include Read or write, Chip enable, and in the case of memory RAS and CAS (row and column activation signal). If the timing is off then the chip does not change the data already stored within it

With those requirements it is highly unlikely to gain corrupted data due to induced voltages from a lightning strike or a solar flare,

the damage from lightning strikes and solar flares typically damage the components. However adequate grounding can and does offer protection. There is though interferance noise in analog signals, but again analog circuits have noise protection, though in some cases the noise is outside the protection design, this doesn't generate a latch up. Instead it generates unrecognized and corrupted data, Error correction codes can regenerate the corrupted bits from a transmission.

 

Thanks. However, while all that is well and good, I am interested in reading references specifically related to solar storm effects on electric grids [& satellites]. I have to wonder why if everything is well protected, there is concern still being expressed as in my earlier link in post #7 on the 2012 near-miss event. ?

Edited June 24, 2014 by Acme

[Mordred]

fair enough the only articles I have deal mainly with lightning strikes, and they are quite lengthy ie too large to post (not even sure if I can attach them due to the size)

A key difference between lightning and a solar flare is the amount of area of induced current and the duration

Edited June 24, 2014 by Mordred

[Hazel M]

Solar flares. Are these the same solar flares that used to interfere with radio reception? And why don't we get that interference any more? Better-built, better-grounded radio and wire?

[Acme]

fair enough the only articles I have deal mainly with lightning strikes, and they are quite lengthy ie too large to post (not even sure if I can attach them due to the size)

A key difference between lightning and a solar flare is the amount of area of induced current and the duration

Acknowledged. Note there is also a key difference between solar flares and CME's. Flares erupt from sunspot regions, CME's not necessarily so.

Solar flares. Are these the same solar flares that used to interfere with radio reception? And why don't we get that interference any more? Better-built, better-grounded radio and wire?

They do interfere with radio. It may be the case that AM is more susceptible and that is reflected in your personal experience.

 

Solar Flares and Disturbances for Radio Propagation

- an overview of the basics of solar flares and other disturbances including CMEs and how they affect ionospheric HF radio propagation conditions for two way radio communications, maritime mobile radio communications, point to point radio communications and radio broadcasting.

As electromagnetic waves, and in this case, radio signals travel, they interact with objects and the media in which they travel. As they do this the radio signals can be reflected, refracted or diffracted. These interactions cause the radio signals to change direction, and to reach areas which would not be possible if the radio signals travelled in a direct line.

 

The condition of the Sun has a major impact on ionospheric radio propagation. Accordingly it affects a variety of forms of HF radio communications including two way radio communications, maritime mobile radio communications, general mobile radio communications using the HF bands, point to point radio communications, radio broadcasting and amateur radio communications.

...

.

Additional flare vs CME info:

 

Solar Flares and Coronal Mass Ejections

There is often confusion about the difference between solar flares and coronal mass ejections (CMEs). Both solar flares and CMEs are energetic events which occur on the Sun. These events are both associated with high energy particles. In the case of a CME, coronal material is ejected into space at high speeds, sometimes in the direction of Earth. Both flares and CMEs depend on magnetic fields on the Sun.

 

Image Credit: SOHO _______________________________Image Credit: TRACE

 

The most obvious difference between a solar flare and a CME is the spatial scale on which they occur. Flares are local events as compared to CMEs which are much larger eruptions of the corona. The left image above shows a bright solar flare erupting in an active region on the Sun. The image on the right shows a CME exploding off the Sun. Notice that this CME is even larger than the Sun itself, which is represented by the white circle in the middle of the frame. Solar flares and coronal mass ejections often occur together, but each can also take place in the absence of the other. The next pages will discuss flares and CMEs in more detail. ...

Edited June 24, 2014 by Acme

[Hazel M]

Yes, of course. AM vs FM and I am always on FM. Solar winds, solar flares, CMEs ----Some do get through to Earth despite our magnetic field?

[Acme]

Yes, of course. AM vs FM and I am always on FM. Solar winds, solar flares, CMEs ----Some do get through to Earth despite our magnetic field?

Yes; many get through. This is most dramatically seen in the aurorae, which occur when Earth's magnetic field redirects charged particles to the poles.

 

Edited June 24, 2014 by Acme

[Hazel M]

Pretty. I like the one on the lower left. Like and invasion.

[Johnny Electriglide]

NOVA Magnetic Pole Flip 530,000 Years Overdue & Happening

 

Strength is down 15% in the past 10 years. I wonder why in past reversals, that a CME never sterilized the surface, or a cosmic ray burst. From what I read, the reversals usually took 50 to 250 years to complete, with up to a 90% weakening of the magnetosphere. It shows that Earth has been lucky, with that at least, but not with humans destroying the biosphere in a GTEE unless they stop polluting now and fall 50% in numbers, or Katla has a big one, or Yellowstone blows.

[Quarkylife]

Yes; many get through. This is most dramatically seen in the aurorae, which occur when Earth's magnetic field redirects charged particles to the poles.

 

 

nice images

[Acme]

NOVA Magnetic Pole Flip 530,000 Years Overdue & Happening

h**ps://www.youtube.com/watch?v=pGKKzsRjJ_Y

 

Strength is down 15% in the past 10 years. I wonder why in past reversals, that a CME never sterilized the surface, or a cosmic ray burst. From what I read, the reversals usually took 50 to 250 years to complete, with up to a 90% weakening of the magnetosphere. It shows that Earth has been lucky, with that at least, but not with humans destroying the biosphere in a GTEE unless they stop polluting now and fall 50% in numbers, or Katla has a big one, or Yellowstone blows.

It is because as Enthalpy correctly pointed out in post #6 it is the atmosphere that keeps [most] high energy particles from reaching the ground. The aurorae colors vary depending on which atmosphere gas atoms are struck by the high energy particles. From my earlier Wiki link:

...

Auroral colors

●Red: At the highest altitudes, excited atomic oxygen emits at 630.0 nm (red); low concentration of atoms and lower sensitivity of eyes at this wavelength make this color visible only under some circumstances with more intense solar activity. The low amount of oxygen atoms and their very gradually diminishing concentration is responsible for the faint, gradual appearance of the top parts of the "curtains".

●Green: At lower altitudes the more frequent collisions suppress this mode and the 557.7 nm emission (green) dominates; fairly high concentration of atomic oxygen and higher eye sensitivity in green make green auroras the most common. The excited molecular nitrogen (atomic nitrogen being rare due to high stability of the N2 molecule) plays its role here as well, as it can transfer energy by collision to an oxygen atom, which then radiates it away at the green wavelength. (Red and green can also mix together to pink or yellow hues.) The rapid decrease of concentration of atomic oxygen below about 100 km is responsible for the abrupt-looking end of the bottom parts of the curtains.

●Yellow and pink are a mix of red and green or blue.

●Blue: At yet lower altitudes atomic oxygen is not common anymore, and ionized molecular nitrogen takes over in visible light emission; it radiates at a large number of wavelengths in both red and blue parts of the spectrum, with 428 nm (blue) being dominant. Blue and purple emissions, typically at the bottoms of the "curtains", show up at the highest levels of solar activity.[13]

...

The rest of your post is off-topic here.

Edited June 24, 2014 by Acme