View Single Post
Old 8th January 2011, 11:07 PM   #1610
Tim Thompson
Tim Thompson's Avatar
Join Date: Dec 2008
Posts: 975
Lightbulb Solar "Electrical Discharges" I

Originally Posted by Michael Mozina View Post
I'll be happy to exclude/include (depending on how you want to see it) you too Tim if you're willing to accept that discharges happen in plasma and you agree to *SOME* definition of an electrical discharge in a plasma. At least then we'll have a place to begin. I think tusenfem and I can communicate, maybe you and I can do that too. Do you accept either Peratt's definition of a discharge in a plasma or Dungey's definition?
First, allow me to reference my own previous comments on this point:
Originally Posted by Tim Thompson View Post
As we have seen in the last several pages, and especially the very informative post 1441 from tusenfem, what the words "electric discharge" actually means seem to be user dependent. It would appear that Mozina wishes to limit the meaning to the phrase "An electrical discharge is a sudden release of electric or magnetic stored energy" ignoring everything else. I have always argued that electrical discharges were impossible in a plasma, but then I always simply assumed that the words meant what everybody would naturally expect them to mean in a colloquial sense, the catastrophic reunion of separated charges across a breakdown potential (lightning, for instance). Only now, after so many years, has Mozina actually defined those words and only now do I (we) realize that the colloquial meaning is not what he had in mind (or at least not what he has in mind now).

It seems to me that whether or not one wishes to call the hot plasma an "electrical discharge" is not really the point. It is certainly a poor choice of words, designed to generate confusion in the absence of a constantly repeated definition. But the real issue is the physics that underlies the words. What physically is really happening is the point. This is where Mozina runs into the brick wall of physics and catastrophically fails the test. He rejects magnetic reconnection in favor of exploding double layers, even though physics rejects the latter in favor of the former. He rejects the frozen flux approximation for magnetic fields in a plasma even though physics requires it. These two points are the most fundamental and critical points in this entire discussion. Everything in the physics of coronal heating, coronal loops, flares & CME's stems from these two critical concepts (with some thermodynamics & radiative transfer thrown in, but they don't yet seem to be points of contention).

As long as Mozina rejects these two critical concepts of physics, magnetic reconnection and the frozen flux approximation, then this discussion and all other similar discussions everywhere are doomed at once to become infinite loops of the same thing over & over & over & over again, ad infinitum, as has become the case for this discussion. Quite simply it's Mozina vs. physics, and I choose physics over Mozina every time.
See tusenfem's post 1441, linked above, where we find tusenfem quoting you quoting Peratt: "An electric discharge is a sudden release of electric or magnetic stored energy. This generally occurs when the electromagnetic stress exceeds some threshold for breakdown that is usually determined by small scale properties of the energy transmission medium" and tusenfem comments, "I note the MM just highlights magnetic energy, whereas, as usual, he forgets about the rest of the text."

Now, to answer your question, I do not think that the definition you present is Peratt's definition, I think it is your own definition; certainly a variation on Peratt's, but sufficiently restricted to count as your own interpretation and therefore your own definition. I would not use that definition on the grounds that it is overly general, and I reject it. I require a breakdown of a potential barrier to qualify as an electrical discharge. Therefore I continue to maintain that, by my definition, "electrical discharges" are impossible in a plasma. However, I am cognizant of the fact that by your specific definition of "electrical discharge" ("An electric discharge is a sudden release of electric or magnetic stored energy.") then "electrical discharges" do occur in a plasma. But I maintain that, whether or not I (or anyone else) "accepts" your definition of "electrical discharge" is in fact not relevant. What is relevant is whether or not you use your own chosen definition in a physically reasonable and self consistent manner. That said I will further maintain that you do not use your own definition in a physically reasonable or self consistent manner, and therefore it is fair to say that you yourself reject what you have come to call "Peratt's definition" (which is in fact your own definition).

You fail to use your own definition in a self consistent manner because, as you say, the release of "magnetic stored energy" counts as an "electrical discharge". While there is a unified science of electromagnetism, this should not be construed to imply that "electrical" and "magnetic" are indistinguishable. The release of magnetic stored energy simply is not electrical so it is not self consistent to call it "electrical". And you do not use your own definition in a physically reasonable way because you want flares to be generated by exploding double layers in a physical environment that is not conducive to the generation of plasma double layers (although I defer to the expertise of tusenfem who's PhD research is on the specific topic of plasma double layers). You also reject magnetic reconnection, which definitely happens in real laboratory plasmas, and which definitely counts as the release of stored magnetic energy, and is therefore an "electrical discharge" by your definition (though not by mine).

Bottom Line: It all really boils down to what I said before and quoted above, that it does not really matter how one wishes to define the words "electrical discharge"; as long as we talk about that we simply avoid the real issue altogether. The real issue is simply this: What is (are) the physical process(es) of energy release that trigger flares & CME's? You (Mozina) say magnetic induction & exploding double layers. Physics, on the other hand, says mostly magnetic reconnection, with some magnetic induction, magnetic buoyancy and rarely (if ever) exploding double layers. As long as this difference lasts, we are at an impasse between Mozina & physics. It's just that simple.
The point of philosophy is to start with something so simple as not to seem worth stating, and to end with something so paradoxical that no one will believe it. -- Bertrand Russell
Tim Thompson is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Back to Top