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EMP effects

Discussion in 'Atomic Bombs In the Pacific' started by Hummel, Dec 15, 2013.

  1. Hummel

    Hummel Member

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    I looked around on the forum for something that might deal with this, but Maggie's Drawers. Does anyone know if Fat Man or Little Boy generated EMP effects to any degree? If so, were there results on board either The Enola Gay or Bock's Car or on the ground outside the blast zone? Do A-bombs generate EMP or is that a phenomenon limited to the thermonuclear horrors? Thank you in advance, folks!
    Oh, today's my 10th wedding anniversary, and, for those who remember what my wife and I went through last year with her hip resection, Susan is up and walking WITHOUT a cane or walker -- for short distances. For longer distances, she has a walker and/or a scooter. I credit, at least in part, the good thoughts and prayers of my brother and sister human beings on this board for that result. So, from Susan and me both, thank you. Thank you. Thank you. Be well and blessed be! May the Goddess watch over you.
    P.S. Sorry about the huge font size -- bad eyes. Joyous Yule to one and all!
     
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  2. jimmytwohand

    jimmytwohand New Member

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    Happy Anniversary.

    I would also be interested to know if there were any EMP results recorded at the time. However i doubt it.

    The EMP is created as a result of a process called Compton Scattering. Simply put the Gamma Rays ejected from a nuclear device collide with atoms and eject electrons which collide with more molecules ejecting more electrons in a similar process to that of the original fission.

    The movement of these electrons caused by the electromagnetic field of the earths atmosphere then give rise to electro magnetic radiation (I think of it like a radio signal) which due to its near (or possibly even) light speed means that radiation from different points will basically all arrive at a given point at nearly the same time like a tsunami overloading equipment it couples to.

    The EMP is not even one homogenised phenomenon it consists of 3 parts normally referred to as E1 through E3. The process above is that to create E1, the fastest and highest amplitude of the 3. I have described this as it is the most likely to cause problems with the small aerials and wiring looms of the types of vehicles you describe (although to complicate matters bear in mind E1 is also the least affected by weapon yield).

    I do not pretend to understand this. ;) However for the purposes of kicking up a debate here's the main reasons why i hypothesise not a lot would have been felt in regard to EMP.

    The lower the weapon is detonated, the lower the effect of EMP (generally) as the electromagnetic field is smaller and there is less time and matter to travel through to produce reaction. The Hiroshima and Nagasaki bombs were ground effect more than airburst (in this very general explanation i'm talking over 20-30km altitude) Therefore the effects of EMP would have been reduced as the stuff affected by the EMP was also affected momentarily later by being vaporised into miniscule flying bits.

    The EMP effect is also Line of Sight, lower atitude - less of the horizon it will reach.

    The further away from the equator you go the higher the geomagnetic field and so generally the higher the EMP spike will be.

    Increasing yield will add EMP very generally speaking but more modern weapons are much more efficient (so less gammas flying off) but of higher yield (also must mention that ionisation will also neutralise some EMP effects and higher yield weapons produce more ionisation).

    The vacuum tube technology of the time was actually also more resistant to the various parts of EMP as it was less sensitive.

    For these reasons i cant see it being an issue with LB or FM.
    I also would be interested if anyone knows different though or is more scientmatifically inclined. Great question.

    Bookmarks i found useful when looking at it.
    http://web.ornl.gov/sci/ees/etsd/pes/pubs/ferc_Meta-R-320.pdf
    http://www.thespacereview.com/article/1549/1
    Fancy EMPing the US?http://empcover.com/EMP-Attack-Simulation.html
     
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  3. steverodgers801

    steverodgers801 Member

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    If there had been anything that was vulnerable to EMP, then yes. The only thing I can think of would be power lines, but Im not sure if they were made of anything that could be fried by the EMP.
     
  4. lwd

    lwd Ace

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    The power lines per se are not that vulnerable from what I recall but EMP can induce a significant current in them. Enough to trip circuit breakers/fuses or destroy sensative equipment. Probably went unnoticed due to all the other factors at the time if there was much of an impact.
     
  5. Otto

    Otto Rested & Resupplied with MREs. Staff Member WW2|ORG Editor

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    Happy 10th Hummel. Here is to another 10 years of health and happiness.

    Nice info J2H, I've thought of the Hiroshima/Nagasaki EMP effects a few times, but never delved into it. Glad this is getting some attention.
     
  6. jimmytwohand

    jimmytwohand New Member

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    The soviets conducted the "K" tests over Kazakhstan in the 60s and with their poor infrastructure and dated technology its not a bad reference point. They haven't released much data though and they are using much larger yields in very high altitude detonations. Power lines are also about all i can think of that might have been affected but not vaporised.

    Some nice equations with good attribution to work out the exact forces we are dealing with if any mathematicians want to plug in the figures:
    EMP SURFACE BURST EQUATIONS DERIVED FROM GRAPHS IN PHILIP J. DOLAN, CAPABILITIES OF NUCLEAR WEAPONS, DNA-EM-1, CHANGE 1
    http://nige.files.wordpress.com/2011/03/surface-burst-emp-formulae-by-nigel-cook.pdf

    Fat man 21kt @ 500m
    Little boy 16kt @ 600m
    Not sure about the ground conductivity in the areas concerned....

    Is the data from Trinity declassified yet? I can't find more than summaries. It's mentioned in a few places that the EMP results were well documented therein and subsequent tests don't seem to have the same combination of low yield and ground burst.

    Great question. Deserves a look into by someone more qualified.
     
  7. steverodgers801

    steverodgers801 Member

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    archive.org/details/theeffectsoftheatomicbombonhiroshima
    website states that there was damage to electrical stations probably due to EMP.
     
  8. lwd

    lwd Ace

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    That sounds reasonable. Thanks for finding a source.
     
  9. jimmytwohand

    jimmytwohand New Member

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    Good link. Thumbs up for chapter 7. It does seem like they didn't really get a grip on the subject until the 50's though so i'm not sure whether there will be any direct data to be dug up. The maths involved is.... well, beyond me.
     
  10. von Poop

    von Poop Waspish WW2|ORG Editor

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    I was in the ROC in the late 80s (mostly because my Dad was, and for it's association with a very nice Winchester pub... please don't take that as any indication of actual 'service').
    We had a little Faraday room at HQ, and speculated on the equipment being archaic for some technical/durability reason associated with EMP, but when it came to training on the subject the base truth was; nobody was quite certain about it's potential effects in the real world.
    I think the fact the trained-for scenarios usually involved most of the country becoming a fly-blown pool of ash & the rest desperately focused on avoiding clouds of poison sort of moved the possibility of the odd airliner coming down and comms arrays being disrupted into the 'lesser issues' camp.

    We might worry more now, with the microprocessor so prevalent & electronics reaching so deeply into all things (though modern electronics are really quite robust/shielded these days for a variety of non-nuclear reasons), but in WW2 I really can't see it having had quite so much potential significance, particularly when you factor in that Fat Man & Little Boy were mere fireworks when compared to rapid postwar bang escalation.
     
  11. sdmahaneysc

    sdmahaneysc New Member

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    When I looked into this I was actually disappointed to find that nothing much would happen to 1940s electronics, especially from (relatively) tiny 1940s nukes. For X-Day: Japan I could only hint at some radio interference.

    Overall, 20 kiloton bombs were practically useless militarily. They could destroy a dense city center, but only chip away at a long battle line of entrenched infantry. I really didn't think of it that way at the start. I expected in gaming to reach a stalemate because of a nuclear "DMZ" being created. Instead it was more reasonable to say resistance simply wasn't broken.
     

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  12. gaweidert

    gaweidert New Member

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    Technology at the time was all tubes, motors and incandescent lighting. None of these are really suseptable to EMP's. To a tube, and EMP is like a mosquito biting an elephant. Just not enough current there to do any damage. Of course with solid state electrical components, the voltage shock from various EMP's fries them every day.


    Soem scientists were not even sure that Enola Gay was even going to be able to get far enough away to be able to survive the blast wave. They had a calculated distance they had to be away, but no one was exactly sure. When the blast wave hit the ship someone called out "flak!" becasue that it waht it felt like when it hit the plane. We did know that there were some 200 American POW's in Hiroshima at the time the bomb was dropped. I think 3 survived the blast.
     
  13. Takao

    Takao Ace

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    I think you mean about 20. I have seen numbers ranging from 11 to 24. What is certain is that the surviving crewmembers from that B-24s “Lonesome Lady” and “Taloa” were being held in Hiroshima Castle as POWs, as well as a scattering of other pilots and crewmen.
    AFAIK, the 3 American POWs that did survive the blast were "Lonesome Lady" gunner Staff sergeant Ralph Neal, US Navy Airman 3rd Class Normand Brissette, and an unnamed American aviator. Neal and Brissette both died horrible deaths from radiation sickness in the days following the Hiroshima bombing, and the unnamed American aviator was beaten to death by vengeful Hiroshima survivors.
     

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