Editing Nuclear electromagnetic pulse (section)

==History==
The fact that an electromagnetic pulse is produced by a nuclear explosion was known in the earliest days of nuclear weapons testing. The magnitude of the EMP and the significance of its effects were not immediately realized.<ref name="science">{{cite journal |last1=Broad |first1=William J. |author-link1=William Broad |date=1981-05-29 |title=Nuclear Pulse (I): Awakening to the Chaos Factor |url= |format= |department= |journal=[[Science (journal)|Science]] |language=en |volume=212 |issue=4498 |pages=1009–1012 |eissn=1095-9203 |issn=0036-8075 |jstor=1685472 |pmid=17779963 |bibcode=1981Sci...212.1009B |lccn=17024346 |oclc=1644869 |df=dmy-all |doi=10.1126/science.212.4498.1009}}</ref>

During the [[Trinity (nuclear test)|first United States nuclear test]] on 16 July 1945, electronic equipment was shielded because [[Enrico Fermi]] expected the electromagnetic pulse. The official technical history for that first nuclear test states, "All signal lines were completely shielded, in many cases doubly shielded. In spite of this many records were lost because of spurious [[Current collector|pickup]] at the time of the explosion that paralyzed the recording equipment."<ref>{{cite report |last1=Bainbridge |first1=K. T. |date=May 1976 |title=Trinity |publisher=[[Los Alamos Scientific Laboratory]] |page=53 |docket=LA-6300-H |via=[[Federation of American Scientists]] |df=dmy-all |url=https://sgp.fas.org/othergov/doe/lanl/docs1/00317133.pdf |access-date=2022-08-10 |url-status=live |archive-url=https://web.archive.org/web/20211009002725/https://sgp.fas.org/othergov/doe/lanl/docs1/00317133.pdf |archive-date=2021-10-09}}</ref>{{rp|page=53}} During [[British nuclear tests at Maralinga|British nuclear testing]] in 1952–53, instrumentation failures were attributed to "[[radioflash]]", which was their term for EMP.<ref name="baum1">{{cite journal |last1=Baum |first1=Carl E. |author-link1= |date=May 2007 |title=Reminiscences of High-Power Electromagnetics |journal=[[IEEE Transactions on Electromagnetic Compatibility]] |language=en |volume=49 |issue=2 |pages=211–218 |eissn=1558-187X |issn=0018-9375 |jstor=1685783 |s2cid=22495327 |lccn=sn78000466 |oclc= |df=dmy-all |doi=10.1109/TEMC.2007.897147}}</ref><ref name="baum2">{{cite journal |last1=Baum |first1=Carl E. |author-link1= |date=June 1992 |title=From the electromagnetic pulse to high-power electromagnetics |journal=[[Proceedings of the IEEE]] |language=en |volume=80 |issue=6 |pages=789–817 |issn=0018-9219 |lccn=86645263 |oclc=807623131 |df=dmy-all |doi=10.1109/5.149443}}</ref>

The first openly reported observation of the unique aspects of high-altitude nuclear EMP occurred during the [[helium balloon]]-lofted Yucca nuclear test of the [[Hardtack I]] series on 28 April 1958. In that test, the electric field measurements from the 1.7 kiloton weapon exceeded the range to which the test instruments were adjusted and was estimated to be about five times the limits to which the oscilloscopes were set.
The Yucca EMP was initially positive-going, whereas low-altitude bursts were negative-going pulses. Also, the [[polarization (waves)|polarization]] of the Yucca EMP signal was horizontal, whereas low-altitude nuclear EMP was vertically polarized. In spite of these many differences, the unique EMP results were dismissed as a possible [[wave propagation]] anomaly.<ref name="yucca">Defense Atomic Support Agency. 23 September 1959. [http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA369152 "Operation Hardtack Preliminary Report. Technical Summary of Military Effects] {{Webarchive|url=https://web.archive.org/web/20130620061706/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA369152 |date=2013-06-20}}. Report ADA369152". pp. 346–350.</ref>

The [[high-altitude nuclear explosion|high-altitude nuclear tests]] of 1962, as discussed below, confirmed the unique results of the Yucca high-altitude test and increased the awareness of high-altitude nuclear EMP beyond the original group of defense scientists. The larger scientific community became aware of the significance of the EMP problem after a three-article series on nuclear EMP was published in 1981 by [[William J. Broad]] in ''[[Science (journal)|Science]]''.<ref name="science"/><ref>{{cite journal |last1=Broad |first1=William J. |author-link1=William Broad |date=1981-06-05 |title=Nuclear Pulse (II): Ensuring Delivery of the Doomsday Signal |url= |format= |department= |journal=[[Science (journal)|Science]] |language=en |volume=212 |issue=4499 |pages=1116–1120 |eissn=1095-9203 |issn=0036-8075 |jstor=1685373 |pmid=17815204 |bibcode=1981Sci...212.1116B |lccn=17024346 |oclc=1644869 |df=dmy-all |doi=10.1126/science.212.4499.1116}}</ref><ref>{{cite journal |last1=Broad |first1=William J. |author-link1=William Broad |date=1981-06-12 |title=Nuclear Pulse (III): Playing a Wild Card |url= |format= |department= |journal=[[Science (journal)|Science]] |language=en |volume=212 |issue=4500 |pages=1248–1251 |eissn=1095-9203 |issn=0036-8075 |jstor=1685783 |pmid=17738820 |bibcode=1981Sci...212.1248B |lccn=17024346 |oclc=1644869 |df=dmy-all |doi=10.1126/science.212.4500.1248}}</ref>

===Starfish Prime===
{{Main article|Starfish Prime}}
In July 1962, the US carried out the [[Starfish Prime]] test, exploding a {{convert|1.44|MtonTNT|abbr=on|lk=on}} bomb {{convert|400|km|mi ft|||}} above the mid-Pacific Ocean. This demonstrated that the effects of a [[high-altitude nuclear explosion]] were much larger than had been previously calculated. Starfish Prime made those effects known to the public by causing electrical damage in [[Hawaii]], about {{convert|1445|km}} away from the detonation point, disabling approximately 300 streetlights, triggering numerous burglar alarms and damaging a microwave link.<ref name="vittitoe">{{cite report |last1=Vittitoe |first1=Charles N. |date=1989-06-01 |title=Did High-Altitude EMP Cause the Hawaiian Streetlight Incident? |publisher=[[Sandia National Laboratories]] |df=dmy-all |url=https://ece-research.unm.edu/summa/notes/SDAN/0031.pdf |access-date=2020-09-15 |url-status=live |archive-url=https://web.archive.org/web/20200823035223/http://ece-research.unm.edu/summa/notes/SDAN/0031.pdf |archive-date=2020-08-23}}</ref>

Starfish Prime was the first success in the series of United States high-altitude nuclear tests in 1962 known as [[Operation Fishbowl]]. Subsequent tests gathered more data on the high-altitude EMP phenomenon.

The [[Operation Fishbowl#Bluegill Triple Prime|Bluegill Triple Prime]] and [[Operation Fishbowl#Kingfish|Kingfish]] high-altitude nuclear tests of October and November 1962 in Operation Fishbowl provided data that was clear enough to enable physicists to accurately identify the physical mechanisms behind the electromagnetic pulses.<ref name="nbcreport">{{cite journal |last1=Longmire |first1=Conrad L. |author-link1=Conrad Longmire |journal=NBC Report |date=2004 |pages=47–51 |publisher=U.S. Army Nuclear and Chemical Agency |issue=Fall/Winter |title=Fifty Odd Years of EMP |url=https://www.futurescience.com/emp/NBC_Report_Fall_Winter04.pdf}}</ref>

The EMP damage of the Starfish Prime test was quickly repaired due, in part, to the fact that the EMP over Hawaii was relatively weak compared to what could be produced with a more intense pulse, and in part due to the relative ruggedness (compared to today)<ref>{{cite thesis |last=Reardon |page=53 |first=Patrick J. |date=2014 |location=Fort Leavenworth |title=The Effect of an Electromagnetic Pulse Strike on the Transportation Infrastructure of Kansas City |type=Master's Thesis |chapter=Case Study: Operation Starfish Prime Introduction & EMP analysis |publisher=U.S. Army Command & General Staff College |chapter-url=https://www.hsdl.org/c/view?docid=762798 |access-date=2019-07-26}}</ref> of Hawaii's electrical and electronic infrastructure in 1962.<ref name="tn353">{{cite report |docket=Theoretical Notes – Note 353 |date=March 1985 |title=EMP on Honolulu from the Starfish Event |last1=Longmire |first1=Conrad L. |author-link1=Conrad Longmire |publisher=Mission Research Corporation |via=[[University of New Mexico]] |url=https://ece-research.unm.edu/summa/notes/TheoreticalPDFs/TN353.pdf}}</ref>

The relatively small magnitude of the Starfish Prime EMP in Hawaii (about 5.6 kilovolts/metre) and the relatively small amount of damage (for example, only 1% to 3% of streetlights extinguished)<ref>{{cite journal |last1=Rabinowitz |first1=Mario |date=October 1987 |title=Effect of the Fast Nuclear Electromagnetic Pulse on the Electric Power Grid Nationwide: A Different View |journal=IEEE Transactions on Power Delivery |volume=2 |issue=4 |pages=1199&ndash;1222 |arxiv=physics/0307127 |s2cid=37367992 |issn=1937-4208 |lccn=86643860 |oclc=1236229960 |doi=10.1109/TPWRD.1987.4308243}}</ref> led some scientists to believe, in the early days of EMP research, that the problem might not be significant. Later calculations<ref name="tn353"/> showed that if the Starfish Prime warhead had been detonated over the northern continental United States, the magnitude of the EMP would have been much larger (22 to 30 kV/m) because of the greater strength of the [[Earth's magnetic field]] over the United States, as well as its different orientation at high latitudes. These calculations, combined with the accelerating reliance on EMP-sensitive microelectronics, heightened awareness that EMP could be a significant problem.<ref>{{cite book |editor-first=Mark |editor-last=Cancian |date=2018 |title=Project on Nuclear Issues: A Collection of Papers from the 2017 Conference Series & Nuclear Scholars Initiative (CSIS Reports) |page=24 |publisher=Center for Strategic & International Studies |isbn=978-1442280557 |url=https://books.google.com/books?id=msVNDwAAQBAJ&pg=PA24 |access-date=2019-07-26}}</ref>

===Soviet Test 184===
{{Main article|Soviet Project K nuclear tests}}
In 1962, the [[Soviet Union]] performed three EMP-producing nuclear tests in space over Kazakhstan, the last in the "[[Soviet Project K nuclear tests]]".<ref>{{cite journal |last1=Zak |first1=Anatoly |title=The K Project: Soviet Nuclear Tests in Space |journal=The Nonproliferation Review |volume=13 |issue=1 |date=March 2006 |pages=143–150 |s2cid=144900794 |issn=1746-1766 |lccn=2008233174 |oclc=173322619 |doi=10.1080/10736700600861418}}</ref> Although these weapons were much smaller (300 [[nuclear weapon yield|kiloton]]) than the Starfish Prime test, they were over a populated, large landmass and at a location where the Earth's magnetic field was greater. The damage caused by the resulting EMP was reportedly much greater than in Starfish Prime. The [[geomagnetic storm]]–like E3 pulse from Test 184 induced a current surge in a long underground [[power line]] that caused a fire in the [[power plant]] in the city of [[Karaganda]].{{citation needed|date=August 2016}}

After the [[dissolution of the Soviet Union]], the level of this damage was communicated informally to US scientists.<ref>{{cite web |title=Subject: US-Russian meeting – HEMP effects on national power grid & telecommunications |last1=Seguine |first1=Howard |date=1995-02-17 |website=[[Office of the Secretary of Defense]] |via=The Nuclear Weapon Archive |df=dmy-all |url=https://nuclearweaponarchive.org/News/Loborev.txt |url-status=live |archive-url=https://web.archive.org/web/20220627232815/http://nuclearweaponarchive.org/News/Loborev.txt |archive-date=2022-06-27}}</ref> For a few years US and Russian scientists collaborated on the HEMP phenomenon. Funding was secured to enable Russian scientists to report on some of the Soviet EMP results in international scientific journals.<ref name="combatwmd">{{cite journal |last1=Pfeffer |first1=Robert |last2=Shaeffer |first2=D. Lynn |journal=Combating WMD Journal |publisher=United States Army Nuclear and CWMD Agency (USANCA) |date=2009 |issue=3 |pages=33–38 |title=A Russian Assessment of Several USSR and US HEMP Tests |via=[[Defense Technical Information Center]] |df=dmy-all |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a495245.pdf |url-status=live |archive-url=https://web.archive.org/web/20131230233322/http://www.dtic.mil/dtic/tr/fulltext/u2/a495245.pdf |archive-date=2013-12-30}}</ref> As a result, formal documentation of some of the EMP damage in Kazakhstan exists, although it is still sparse in the [[open science|open-scientific]] literature.<ref name="greetsai">{{cite journal |last1=Greetsai |first1=V. N. |last2=Kozlovsky |first2=A. H. |last3=Kuvshinnikov |first3=V. M. |last4=Loborev |first4=V. M. |last5=Parfenov |first5=Y. V. |last6=Tarasov |first6=O. A. |last7=Zdoukhov |first7=L. N. |date=November 1998 |title=Response of long lines to nuclear high-altitude electromagnetic pulse (HEMP) |journal=[[IEEE Transactions on Electromagnetic Compatibility]] |language=en |volume=40 |issue=4 |pages=348–354 |eissn=1558-187X |issn=0018-9375 |lccn=sn78000466 |oclc= |df=dmy-all |doi=10.1109/15.736221}}</ref><ref name="euroem">{{cite conference |last1=Loborev |first1=Vladimir M. |title=Up to Date State of the NEMP Problems and Topical Research Directions |conference=Electromagnetic Environments and Consequences: Proceedings of the EUROEM 94 International Symposium |location=Bordeaux, France |date=1994-05-30 |pages=15–21 |df=dmy-all}}</ref>

For one of the K Project tests, Soviet scientists instrumented a {{convert|570|km|mi|adj=on|sp=us}} section of telephone line in the area that they expected to be affected by the pulse. The monitored telephone line was divided into sub-lines of {{convert|40|to|80|km}} in length, separated by [[repeater]]s. Each sub-line was protected by [[fuse (electrical)|fuses]] and by [[gas-filled tube|gas-filled]] [[overvoltage]] protectors. The EMP from the 22 October (K-3) nuclear test (also known as Test 184) blew all of the fuses and destroyed all of the overvoltage protectors in all of the sub-lines.<ref name="greetsai"/>
Published reports, including a 1998 IEEE article,<ref name="greetsai"/> have stated that there were significant problems with ceramic insulators on overhead electrical power lines during the tests. A 2010 technical report written for [[Oak Ridge National Laboratory]] stated that "Power line insulators were damaged, resulting in a short circuit on the line and some lines detaching from the poles and falling to the ground".<ref name="ORNL-3">{{cite report |last1=Savage |first1=Edward |last2=Gilbert |first2=James |last3=Radasky |first3=William |docket=Meta-R-320 |title=The Early-Time (E1) High-Altitude Electromagnetic Pulse (HEMP) and Its Impact on the U.S. Power Grid |section=Section 3 – A Brief History of E1 HEMP Experiences |date=January 2010 |publisher=Metatech Corporation for Oak Ridge National Laboratories |df=dmy-all |url=https://www.ferc.gov/industries/electric/indus-act/reliability/cybersecurity/ferc_meta-r-320.pdf |access-date=2017-09-08 |url-status=dead |archive-url=https://web.archive.org/web/20170520145500/https://www.ferc.gov/industries/electric/indus-act/reliability/cybersecurity/ferc_meta-r-320.pdf |archive-date=2017-05-20}}</ref>