Magnetic disturbance

Once in a great while, we have a series of events where our machines with beam scanning functions in them will all be steered out of place enough to trigger alarms and shut the units down.

It does take a lot of magnetic disturbance to force these out of alignment, but there is no other equipment adjacent, on the roof nor in the ground. This area of operations are on ground level cement slab and the roof is tin with nothing but static vents. Power feed transformers are far away.. There was no near by strikes which has never cause this in the passed.

The strange thing is, we had to wait ~ 20 mins for a restart because we kept on getting an error in steering, on all the machines, then it finally cleared up..

All these machines are independent of each other..

Is there any geological events that can take place to cause this in the ground or maybe solar charge of some kind? It's almost like some one was hanging a large magnet over our plant.

Jamie

Well, we are getting on towards the solar maximum of the current solar cycle, although it continues to look as if this is going to be a relatively modest solar-max. There have been a number of significant solar flares in the past few months, and I've heard anectodal reports of coronal mass ejections and the resulting geomagnetic storms which were strong enough to trigger some significant auroral activity.

If you've been keeping records as to when these steering disruptions have occurred, you could compare them with the geomagnetic-monitor summaries of the planetary K index. If they seem to line up with periods when the K index is 5 or above, then it's entirely possible that your beams are "feeling" geomagnetic variations due to a big cloud of plasma hitting the ionosphere after a CME.

ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/ has the K index data, down to a 3-hour resolution.

For an interesting read, look up the great Carrington solar flare of

1859, and the resulting geomagnetic storm, and then consider the probable effect on our modern civilization of another storm of this magnitude.

--
Dave Platt                                    AE6EO 
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"Jamie" wrote in message news:nmEis.2752$ snipped-for-privacy@newsfe24.iad...

Does this help, er match up with your distrubance? It's a CME prediction model.

Cheers

Interesting site, looks like a good candidate for an application that could read and display those numbers graphically with a geological plot.

I book marked it, thanks.

Jamie

** Copy of previous posting elsewhere **

Err...What about the possibility of an extremely nasty solar flare storm - one that can literally fry all satellite electronics, and zap almost all ground-based electronics? Refs:

1) EE Times Sep 17,2012 pp 20-22 "Girding for the next 'solar max' " 2) Science Fact article in Analog SF&F Nov 2012 pp21-27 "The Day the Sun Exploded".

Could be serious enough to totally crash all banking in the world,leaving the "Third World" nations in a superior position.

On a sunny day (Fri, 26 Oct 2012 18:58:43 -0400) it happened Jamie wrote in :

The old dirty trick was somebody walking in with one of them super-magnets. Magnetic stripe cards erased, CRT monitors changing color... I do not think there is a natural magnetic effect that big, unless you are located over an underground railway (tube).

Mains fluctuations?

They are. Or rather the planet has a pretty huge magnet inside it and the solar wind can buffet it enough to cause trouble for sensitive gear. More so in the US and Canada than in Europe since magnetic North is on your side of the planet.

Any geomagnetic record for your neck of the woods would show if it was from a CME event. This one goes back a few days

Place to look next time it happens.

You might want to make a simple magnetic disturbance monitor to determine independent of your kit if there is a magnetic storm.

--
Regards, 
Martin Brown

"Martin Brown"

** Thanks Martin.

Despite the OP's staggering lack of insight, the motive for my two suggestions re the magnetic compass and simple CRT type scope was the very same idea.

I also suspect the notion alluded to in the heading is pure hogwash.

.... Phil

Rubbish. Dipole field falls off as 1/r^3.

They are not all that powerful at a distance. At least up to the sizes used for magnetic clamps. You don't want one in a pocket though. I became attached to a supermarket checkout till once after someone put one in one of my pockets. They will nip flesh rather painfully - big ones destructively. Didn't harm my bank card at all.

Superconducting NMR magnets are in a different league altogether. I know of one where the outer shell has a dent from snatching the end of a passing scaffold pole from outside the building.

Again you have to be quite close to magnetise the screen and any damage is fairly local. The one thing I found did zap bank cards was the initial power on degauss coils of big reference colour monitors in the old days if you were leaning over or working on them at switch on.

There was a hefty boing noise from the coils responding to the degauss waveform. That really did for bank cards if you forgot.

Trams? Large arc welding kit nearby. Seen that destroy some early CNC kit after the machine went beserk.

--
Regards, 
Martin Brown

(snip)

Our magnetizer at work will erase those club discount cards that stores give out if you stand within a few feet of it. I think it makes a 1.3T pulse 150ms long with a coil ID of 8 inches. Never had any credit cards get erased though.

Mark DeArman

he

solar flares cause massive disturbances to the earth's magnetic field.

Take a look at the Noise Floor of the Earth's Field: the field noise data cmoes ffrom actual meaurments of sites From paper, here is its bibliography:

1. E.L. Maxwell and D.L. Stone, "Natural Noise Fields 1cps to 100kc", IEEE Transactions on Antennas an Propagation, Volume AP-11, Number 3, pp 339-43, May 1963.

2_ D.A. Chrissan, A.C. Fraser-Smith, Seasonal Variations of Globally Measured ELF/VLF Radio Noise, Technical Report D177-1, Stanford University Dept of Electrical Engineering, STAR Lab, December 1996. 3_ R. Barr, D. Llanwyn Jones, C.J. Rodger, "ELF and VLF radio waves", Journal of Atmospheric and Solar-Terrestrial Physics, Volume 62, Issue 18, pp 1689-1718, November 2000. 4_ Kenneth Davies, Chapter 9, Propagation of Low and Very Low Frequency Waves, Ionospheric Radio Propagation, New York, N.Y., Dover Publications, Inc., 1966. 5_ M. Balser and C.A. Wagner, "Observations of Earth-ionosphere cavity resonances", Nature, Volume 188, pp 638-41, 1960

Magnetic fields are insidious, once created you can't destroy them, simply redirect them. And, low frequency are the worst, because they penetrate EVERYTHING! Using mumetal can get expensive, and if not done properly can easily exacerbate the problem by 'sucking' in magnetic fields and actually intensifying them locally, so even that type of shielding must be done carefully.

from those charts: at 1 Hz the noise spectral density is 'normally' 1pT/rtHz, and it has a 1/f distribution [I think] at 0.01Hz it has climbed to over 1nT/rtHz.

If your e-beams are low speed, circa 10-20kV and the run path is long, it doesn't take much field to deflect the beam over 100nm down at the target, which in today's geometries is HUGE!

Has anybody produced the calculations for you? It should be part of your equipment's performance spec - specifying the operating ambient fields that are allowed. Then it'sup to you to prove your fields are less than that.

Anyway, the number in those charts is 'average' which means during solar storms it can easily go above 10X that value - for days! and even into the 100X for short periods.

Do you have ambient magnetic field instrumentation monitoring the fields? They are purchaseable items.

s

Just thought of something, our satellite reception went wonky the other night/day? during 'good' weather. The satellite company claims moisture in the air during a rainstorm reduces the uWave signal and you get signal breaking up. We got signal breaking up but the weather here was SUNNY and clear! Anybody else experience that? Maybe we can correlate the disturbances we saw to what happened to Jamie.

the

s.

I once took one of those super space magnets [so strong they can make a Canadian dime stand on its edge through your hand] and held it close to my old [favorite] monitor and wow what great color changes. only to find the effects became permanent! not even ON/OFF cycling did a thing. Then I remembered how energetic the fields from my cheap pencil sharpener were, held it close to the screen, sharpened a pencil, and voila! degaussed the nickel layer on the monitor making the color better than before! whew! I was very looky I didn't permanently bend or break that film, too.

I got myself into the same situation years ago. I finally thought to use my big Weller soldering gun as a degausser.

On a sunny day (Sat, 27 Oct 2012 08:37:06 -0700 (PDT)) it happened Robert Macy wrote in :

You have to switch them off, and let them cool for a while. The degaussing coil is fed by some PTC / thermistor.

Shadow mask, I once dropped a color set, mask permanently bended, no way could you get purity back.

I had a real degausing coil in the shop, huge coil, circle in front of the screen. slowly move away, directly fed from main.

On a sunny day (Sat, 27 Oct 2012 08:32:28 -0700 (PDT)) it happened Robert Macy wrote in :

You can break the sat signal by running some machine that sparks, say DC electric motor. I have had total loss of signal when a thunder cloud passed between satellite and my dish, while it was still sunny here (online rain radar show it). I am just recording starwars in HD from sat now:

Should be finished by now, another 11 GB (inclusive commercials):

-rw-r--r-- 1 root root 11423326208 Oct 27 18:38 Astra2_ITV1_HD.16h13.27-10-2012-162m.ts Rarely goes wrong, DVB-S2, QPSK, free to air... As long as bit errors shows zero the recording is perfect, it logs all errors to an error log. Important for editing (the commercials out). Linux, the advantage of writing your own soft is that you know what you are doing. (Else it won't work).

Indeed. A colleaque of mine from Uni Genova told once how his CRT computer screen bent and distorted like the clocks in the "Persistence of Memory" every now and then, at the time his office was above the big hall where some large magnets were tested. I think those magnets were sections going to the Compact Muon Solenoid.

Regards, Mikko

s e

the

s

It can be worse. In the 1980's Cambridge Instruments sold an electron beam microfabricator to GE in the US, to a lab on the east coast. The installation was doing fine until it came to final acceptanace tests, when the patterns being written onto the silicon wafters started showing intermittent step shifts of about half a micron - 500nm - and nobody could work out why.

In a final desperate attempt to solve the problem our senior engineer was flown over to America. He was a technology history buff and was impressed when he got to the GE lab - it was an old building, and the lift they used to get him up the electron beam microfabricator on the first floor was a real antique, dating back perhaps 100 years, which relied on hydraulic pressure to go up and down.

The cylinder which formed the floor of the lift was a very large chunk of magnetic iron. When the lift was at the first floor, it changed the magnetic field at the electron beam microfabricator enough to shift the beam on the specimen by 500nm.

The solution to the problem was not to allow the lift to move while a pattern was being written. The electron beam microfabricator sold for a couple of million dollars, so there was quite a lot of money hanging on the correct diagnosis.

--
Bill Sloman, Sydney

I was in work today and spent about 2 hours zeroing the sensor array around each vault to get proper readings at the computer. What ever happen the other day sort of corrected it self as for the E-Beam, but the sensor array we have hanging around each vault did not fully come back into zero alignment for what ever reason.

The sensors are something we constructed as a way to detect the surroundings with in the critical areas of the E-beam to keep people, metal objects and equipment from being place in proximity of the vault.

If you disturb the area around too much in the area where the E-beam is housed, it will cause the beam to steer off and if bad enough cause heating in the aperture, which isn't a good thing because it can also cause .001" thick titanium window to heat unevenly and thus start a leak.

Heating of the aperture can propagate up the drift tube and bellows which all have gaskets that leak when slightly aggravated.

So, we try to force the system to shut down at the slightest hiccup so there won't be hours or lost time and repair work.

Jamie