View Full Version here: : ITN: Status on Plasma Physics
02-11-2010, 06:12 AM
Ok … so I know Alex will go for broke on this one but I do not feel that this should prevent us from raising a thread on the real status of Plasma Physics.
I am not attempting to provoke arguments … I hope others follow this lead.
As a matter of fact, it would be nice to discuss the topic rationally, for once.
I will state, yet again, that I am not a proponent of Electric Universe or PC. This is a mainstream science thread.
I raise this thread because I do find the topic of interest, and plasma physics clearly impacts the evolution of certain structures in the Universe. The contents capture what may be a reasonably unbiased 'snapshot' of the mainstream status in the area of study.
So, here goes, firstly the journo's article:
Solving the mysteries of the plasma universe (http://www.physorg.com/news/2010-10-mysteries-plasma-universe.html)
and then, more interestingly, the papers from:
The Workshop on Opportunities in Plasma Astrophysics (http://www.pppl.gov/conferences/2010/WOPA/)
The conference papers were presented recently, by real Physicists from around the world. The attendees list is here (http://www.pppl.gov/conferences/2010/WOPA/Regi-list.pdf). The topics discussed were:
Collisionless Shock and Particle Acceleration
Waves and Turbulence
Interfacial and Shear Instabilities
Relativistic, Ultra-strongly Magentized, and Pair Plasmas
Jets and Outflow Including Structure Formation.
Ten major questions were raised on Plasma Physicists.
1. How do magnetic explosions work?
2. How are cosmic rays accelerated to ultrahigh energies?
3. What is the origin of coronae and winds in virtually all stars, including Sun?
4. How are magnetic fields generated in stars, galaxies, and clusters?
5. What powers the most luminous sources in the universe?
6. How is star and planet formation impacted by plasma dynamics?
7. How do magnetic field, radiation and turbulence impact supernova explosions?
8. How are jets launched and collimated?
9. How is the plasma state altered by ultra-strong magnetic field?
10. Can magnetic fields affect cosmological structure formation?
These questions would seem to summarise the present state of understanding of mainstream plasma physics as it pertains to Universe.
Here's hoping I don't get lynched for this one. Where it goes, is up to responders.
I will request the thread to be removed if it goes astray.
02-11-2010, 02:14 PM
Just reading through the draft summary paper on "Relativistic and Strongly Magnetised Plasmas". This paper is a condensed version of whitepapers written by participants of the May 2007 Laboratory Plasma Astrophysics Working Group (LPAWG) meeting.
The quote below pertains to my standing query about the possibilities of lab simulation/scaling of neutron star plasma environments:
Looks like it may actually be possible to simulate the plasma environment in a lab. Ie: finally an answer to one of my long standing questions .. this is progress !
02-11-2010, 02:41 PM
In the same paper, the section on "Turbulence and Reconnection in Relativistic Plasmas" is also very interesting. It talks about the turbulence in fast moving plasmas:
This includes: solar flares, solar wind heating, accretion disks around pre-main sequence stars and compact objects, various interstellar medium processes (proto-stellar clouds), supernova remnants, AGN jets and cluster galaxy processes.
For corona of magnetars, AGN and GRB jets:
All good research/investigation topics which I'm sure would help explain a lot more of the phenomena/observations surrounding these objects.
04-11-2010, 10:50 AM
I found a very interesting example of how they go about calculating the electrical characteristics of a quasar plasma jet, starting from images taken from VLA radio and Chandra X-Ray images. (Too big to attach to this post .. the link is: http://www.pppl.gov/conferences/2010/WOPA/talks/Jets_Kronberg.pdf. WARNING: its 8MBytes).
The way they've presented it, is very clear to the point that I can almost understand it !
3C303 is a Seyfert galaxy with a quasar-like appearance located in the constellation Bootes. The jets are absolutely huge in length.
Their conclusions about it are:
- The 3C303 jet behaves as a galaxy-scale, current-carrying “wire”.
- The jet calculations result in a jet which is consistent with a magnetically confined, 'Poynting flux' driven jet. (ie: Magnetic field constrained).
- The plasma contains very little 'thermal plasma' (ie: the electrons are at a much higher temperature than the neutrals and the ions).
- Current deduced : I = 7.5 x 10∧17 ampères.
- The SMBH system, at the core, "sees’’ an impedance looking into the jet, which is pretty close to the impedance of free space! (About 300 ohms).
- The current is directed AWAY from the galaxy AGN nucleus in the 3C303 knot.
- Intrinsic knot polarization is consistent with a low-field potential, (phi), helical field. (Which is also the field shape which constrains the jets).
The final slide (#22) shows a comparison of typical observable objects. The graph axes are field strengths vs the object size, which helps to visualise the various field strengths by object sizes.
Very interesting. Plasma "wires' do exist in space ! According to mainstream theory, it takes a Supermassive Black Hole to generate the power to make it all happen, though.
04-11-2010, 04:55 PM
It would be great to see Peratt or Scott at this...
Anthony Peratt - Physics of the Plasma Universe
Real Properties of Magnetic Fields in Space:
04-11-2010, 05:17 PM
Your guys weren't at the conference referred to in this (so far) very mainstream oriented thread. I couldn't find them on the attendees list.
There were guys from Los Alamos there but Peratt wasn't.
So far, I've found the thread, very enlightening.
The electrical model I referred to in my last post might help you to model your Relaxation Oscillator. By the way, have your figured out the precision issue yet ?
PS: "Gaede's" video on the double slit ?? .. C'mon .. ?
04-11-2010, 05:57 PM
Close to 100 attendees of Plasma research scientists attended the Workshop on Opportunities in Plasma Astrophysics (which started this thread).
The workshop was hosted by:
- the Princeton Plasma Physics Laboratory,
- The US Department of Energy (Fusion Energy Sciences Program), NASA, the National Science Foundation directorate for Mathematical and Physical Sciences,
- the American Physical Society (APS) Topical Group in Plasma Astrophysics,
- the APS Division of Plasma Physics,
- the Centre for Magnetic Self-Organisation in Laboratory and AstroPhysical Plasmas, (an NSF Physics frontier Centre established in coordination with the US Department of Energy).
And the main point of it was to organise themselves, and their research priorities prior to the US Government's major allocation of science research funding, which was announced about 3 months, (?), ago.
I'd say it was a very reputable gathering of the US's top-notch Plasma scientists. Its a bit of a stretch to think they didn't understand plasma magnetic reconnection principles/theory.
04-11-2010, 09:21 PM
"mainstream", It would be wise to see where these convenient frozen-in-MHD equations originated from Craig, and the list of colleagues. ;)
As astro in a jar in a lab experiment goes, you may be interested in Lerner's series on quasars and radio lobes
yep nearly 30yrs ago....
Particularly relevant as now black holes are magically vanishing in record time. http://spacefellowship.com/news/art23597/cosmic-curiosity-reveals-ghostly-glow-of-dead-quasar.html
whoops.. they are now "shutting down"?? what the? hehehhe... sticky tape?
(come play in the lab... pay attention 10:20 onwards : http://www.youtube.com/watch?v=Kd-tWGWtYwU)
PS: Gaede, good to see you're paying attention... read his book yet?
PPS: Please show me a lab verified experiment of magnetic reconnection... or hey... since we need to reconnect.... show me a magnetic monopole.... until then it's yet more theoretical astro inventions.... not a fan of flapping rubber bands.... field lines don't actually 'exist' brother...
You only ever use a "wire" for a circuit. What type of circuit?
05-11-2010, 11:49 AM
Quasars are certainly a mystery. Lucky science is about asking questions as opposed to coming up with answers !
I notice that the Dense Plasma Focus machine has to be designed (http://en.wikipedia.org/wiki/Dense_plasma_focus#Design_parameter s) to pretty high tolerances to generate a Plasmoid. A deviation of only 10%, if the plasma focus is to operate efficiently.
I wonder what the chances of that happening in nature are ?
Lerner's doing some good research into producing fusion energy here on Earth. Good on him. He should stick with it !
Actually, I found Gaede to be very entertaining. I cracked up at his experiment. (Probably for different reasons than he was intending, though!)
I don't quite understand all the angst about magnetic reconnection .. I mean, chaotic, energetic turbulence in any plasma would cause current flows to change abruptly .. whether its caused by magnetic field reconnection, or interrupted amplified electricity flows is kind of like a chicken and egg debate, isn't it ? (I may not know enough about the controversy/debate here yet, mind you).
The fact that energy is increased within a chaotic flow is enough for me as a reasonable basis for seeing that the coronal heating issue may be caused by external conditions (not excluding acoustics as well). (Ie: rather than modelling it all as an isolated system not obeying the second law themodynamics. If it's not isolated, then no problems, huh ?)
For once, we may have some common thoughts ?
05-11-2010, 12:16 PM
ahh yes, tis why we experiment... Remember the DPF uses the *natural* instabilities of plasma... Princeton and the Tokamak boys are using mechanical and very un-natural ways of confining plasma. Lerner essentially dumps a capacitor bank into the plasma, and 'it' kinks up and does it's own thing, although recently adding an initial m-field to the process.
One fusion solution uses the natural instabilities (which match the morphology of celestial objects)
One does not... and is a very expensive metal doughnut.
Magnetic monopoles or open magnetic fields do not exist. It's an artifact of using perfect-MHD equations.
Regarding the 'experts at Princeton'... see the 8minute mark.... which carries over to here: http://www.youtube.com/watch?v=xaSErR16gPI
Plasmas are *not* "infinitely conductive".
Do you have a solution for the Gaede fringes?
Close.. bit of a stretch tho... invoking alot of ifs... i'd like to see a magnetic reconnection event in the lab first... If they actually make a magnetic monopole, they will make a packet of cash... it would change our economy.... I aint holding my breath tho.
Re: corona... I'm still with the 14yr old... Hot on the outside, warm on the in... colder underneath... It illogical to have a sustained fusion-furnace underneath "powering the whole thing". I'm just hanging around here to see what other gold comes from this young oracle.
Other than that, Craig thanks for posting this here, it's clear plasma physics will play a big role in future astronomy... This are great developments, and the radio telescope funding they are after has my support. Our aussie possum Gaensler is leading the charge.
I'll also now have your post to direct Carl and Bojan too when i get grilled about "wires in space". ;) i know i know, you're only a messenger. ;)
05-11-2010, 02:24 PM
I should be a little clearer again from Wiki ..
My point is that in order to generate one of these plasmoids, the design of the DPF machine is extremely specific. In order to generate one of these puppies, requires very fine tolerances in the design of the equipment. How can this possibly occur in the centre of a galaxy ?
I agree with the last statement.
Moving on though ..
I'm sorry 'brother' .. I couldn't stop laughing enough to take him seriously !
Sorry Alex .. I haven't seen anyone claiming that 'this is what powers the whole thing'. Let it go, man .. (everyone else has).
Yep. We need more solar research. Seems like Solar Probe Plus will be good. Gotta wait until 2015 for launch, though. I don't think anyone here has ever said that space bound plasmas don't have roles to play. The issue seems to be about where they do play and have an impact on things. There's no need to over-generalise here Alex.
Gee .. steady on there. I wanted to examine what questions/approaches mainstream plasma physicists were up to, independently of your views (we've had plenty of this already).
You hijacked my nice, quiet thread (as predicted). ;)
I'm not interested in joining your 'dark-side-of-the-force' perspective.
I do enjoy the conversation, however.
05-11-2010, 02:53 PM
Yes, this *is* Plasma Cosmology, and the basis of Alfven's, Peratt's, Lerner's, and many others modeling and empirical investigations. (You will see some of these details in Lerner's quasar model, plenty more in Peratt's Physics of the Plasma Universe)
I suspect you may be concerned over matters to matching the engineering of the experimental apparatus, rather than what happens once the energy is made available and the plasmoid is forming, and 'natural' processes of self compression are studied.
Remember as plasma scales, so too does the time scales.
PS: Regarding Exploding Double Layers Vs Magnetic Reconnection: http://sites.google.com/site/cosmologyquest/what-we-do-know/magnetic-reconnection (a compilation of works addressing the issue)
05-11-2010, 03:11 PM
Yes, I can see this issue is just like the one raised by your pursuing a design for a relaxation oscillator model which mimics pulsars. The precision of the oscillation is the sticking point there.
And here, the sticking point is that we've managed, using our cleverness and understanding of the fundamental forces, to reproduce something which resembles remarkably, some of the phenomena observed, (visually), in the universe.
Its all so contrived coming from a deliberate intention or preconceived idea. I don't see that that it serves any purpose other than to push that pre-conceived idea.
Sorry Alex but that's pseudoscience, right there.
Having made this rather unpleasant conclusion, (apologies if you're offended), I do concede that the resemblance between the plasmoid created in the DPF machine displays perhaps, superficial (visual) similarities to a quasar. But you know, I could create a clay model of quasar and get the same result.
Does it tell me anything ?
PS: Don't take this personally … I'm just trying to get to the bottom of my discomfort about it all. Then I can deal with the rest. Cheers
06-11-2010, 10:27 AM
Whilst most of the quotes I have extracted from the papers presented in this conference focus on jet plasmas, some of the topics of interest also cover AGN accretion disk plasmas.
I just wanted to cross reference another post, which came up in the News recently, about work going on, which is targetted at investigating the spectra of the accretion plasmas surrounding AGNs.
The post is here (http://www.iceinspace.com.au/forum/showthread.php?p=653374#post653374) .
It appears that lab tests have recently yielded a more accurate baseline for the K-alpha line of iron which, when compared with AGN X-Ray observations, will yield far more accurate redshift information on the accretion plasmas.
(This post is 'just for the record').
10-11-2010, 11:00 AM
You are more than entitled to your own conclusions. However, I do not share your conclusions, probably due to actually reading the material here-posted, thus revealing a psuedoskeptical clay or straw argument?
It seems generally were are entirely comfortable to employ a super natural black hole and computer simulation with free parameters to produce an hypothesis based on 'accretion' 'plasmas' some how driven by the weakest force known to man, gravity.
But seemingly remain uncomfortable at viewing experimental evidence of using electric currents to produce 'real' examples of morphology of cosmic events, in a real world lab, that has developed an hypothesis (which from your post you have not read), using electric currents to produce the morphology, a force many orders of magnitudes beyond those used by super-massive, supernatural events.
Apologies if i do not share your optimism in pursuing the supernatural as a path to understanding. I'll stick to the understood forces available to experimentation as a path of investigation. But hey, maybe the LHC will create a BH, maybe not, they'll use a hell of a lot of electric current in the process. Nature usually takes the easiest path.
Hopefully we can continue to explore the details, i have enjoyed and am aware of the questions and insights to date.
All the best,
PS: Phil's fond of spinning clay (http://blogs.discovermagazine.com/badastronomy/2010/11/04/putting-the-spin-on-saturns-hex/) for answers. Heard he gives classes ;)
10-11-2010, 03:00 PM
There was a post here I think that LHC has already created a mini Big Bang :thumbsup:, Although they did mention could take many years to evaluate the data. I must admit they have started to use LHC@home yet, I have not seen any activity on my PC.
10-11-2010, 08:50 PM
vBulletin® v3.8.7, Copyright ©2000-2017, vBulletin Solutions, Inc.