Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!newsfeed.fsmpi.rwth-aachen.de!news.mixmin.net!aioe.org!.POSTED!not-for-mail From: "Rod Pemberton" Newsgroups: comp.lang.forth Subject: Re: Comet Landing - a triumph for Forth in Hardware and Forth in Software From steering telescopes to steering Philae Date: Fri, 21 Nov 2014 19:56:22 -0500 Organization: Aioe.org NNTP Server Lines: 45 Message-ID: References: <9d07693c-9246-4dce-b1a0-71edcb95be3b@googlegroups.com> <27eae3a5-e450-4f7a-b1b9-1efe24d8f14b@googlegroups.com> NNTP-Posting-Host: i+Urkql2cL38hhKqzSWEjg.user.speranza.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Opera Mail/12.16 (Linux) X-Notice: Filtered by postfilter v. 0.8.2 Xref: csiph.com comp.lang.forth:34551 On Thu, 20 Nov 2014 22:43:14 -0500, wrote: > On Thursday, November 20, 2014 12:04:13 PM UTC-7, Jason Damisch wrote: >> On Wednesday, November 19, 2014 5:58:50 PM UTC-8, hughag...@yahoo.com >> wrote: >>> I have read that it is reasonably easy to radiation-harden >>> the power-generating plants, yet this hasn't been done. >> >> I assert that nuclear power plants should especially be rad-hardened. > > My post conflated an EMP (electromagnetic pulse) caused by a Carrington > Event, with radiation, although they are actually different. > > An EMP will cause current to flow through conductors, causing > electronics to get fried. ... > It is static electricity. Static electricity? No. Induced current. Yes. According to Wikipedia, an EMP can have both an electric field and magnetic field. If the EMP has a magnetic field component, then this could/would induce a current in conductors. I.e., a changing magnetic field induces current, as per Faraday's law of induction. The change is from almost no change in the local magnetic field to a sudden magnetic field from the EMP pulse. If the magnetic field is sufficiently large, the induced current could be large enough to burn up traces, resistors, inductors, destroy ICs and damage static sensitive components. It's very possible that the induced currents are minimal even for a very large EMP. My recollection is that most of the field strength laws are inversely proportional to either distance or the square of distance. I.e., the field strength declines rapidly the further you're away from the source. I don't know if that's the case for an EMP pulse. It may just be for things like magnets and electromagnets which have static (non-changing) fields. Rod Pemberton