Moreover, this lab experiment also confirms that the X-rays are emitted ONLY in the presence of MAGNETIC fieldsUmmmwut?
@jonesdave and cantdrive85.
@jonesdave
Please read/comprehend in the specific context...Moreover, this lab experiment also confirms that the X-rays are emitted ONLY in the presence of MAGNETIC fieldsUmmmwut? X-rays are produced for use in imaging by shooting high-energy electrons at a metal target. No magnets involved.
For the experiments the research team fired laser beams onto a plastic foil, which exploded, causing a stream of electrons and ions to be expelled, forming a high speed flow of ionized gas (plasma) LIKE SOLAR WIND. This 'PLASMA FLOW' then impacted onto a solid sphere, the so-called laboratory `COMET', placed nearly a centimetre away from the plastic foil, resembles what happens when a real comet passes through the Solar system. It was found that electrons are heated to about a million degrees in the up-stream plasma by plasma turbulence. These HOT electrons are responsible for EMITTING X-RAYS but only in the presence of a MAGNETIC FIELD.Thanks. :)
Please also see my response to @Da Schneib above. The Magnetic Field aspect/comments related ONLY to above 'plasma flow' situation onto/around COMETS; and the experimenters confirmed there must be HOT (aka FAST) electron currents at comet which MUST BE affected by some Magnetic Field; as per their in-context statement:These hot electrons are responsible for emitting X-rays but only in the presence of a magnetic fieldHigh voltage lightning can be observed in dusty volcanos, the https://www.techn...ch-tape/ can also generate X-rays in vacuum just by friction = magnetic field shouldn't be necessary.
These HOT electrons are responsible for EMITTING X-RAYS but only in the presence of a MAGNETIC FIELD.Thanks. :)
@ Really-Skippy. How you are Cher? I am good me, thanks for asking.Consider the subject matter: COMETS. And ELECTRIC CURRENTS; And MAGNETIC FIELDS.@jonesdave and cantdrive85.
And,@jonesdave
Cher, I think you are on the wrong article. They did not chime in on this one yet. You need to look in on the other articles where they are arguing unless you just wanted that they argue on this one too.
what are the chances of that happening this time, Ira?Well knowing the can't-Skippy like I do know him, I would say your chances are about zero, maybe less.
@RC, actually it's not synchrotron radiation, it's bremsstrahlung. Synchrotron radiation is polarized; bremsstrahlung is not. And that's only one of its signatures.Again, please pay particular attention to the situation/context. For example, it's NOT 'braked' electrons, it's 'accelerated' (to fast/hot motional state) electrons; hence NO 'Bremsstrahlung' (braking radiation) as such; moreover, it's NOT motion through 'neutral' (eg, atomic/molecular gaseous) media; but rather, through conductive PLASMA; so the 'study target' phenomena/radiation involved in this situation is therefore Synchrotron Radiation from fast-electrons moving in 'accelerating/spiraling manner' along Magnetic Fields, which the team also specifically state must BE there in such 'plasma flow' situation at/around comet moving/interacting with Solar Wind and 'local plasma flows' at comet itself (which give rise to 'shock heated/accelerated fast-electron currents as described by team). :)
See for example https://www.scien...5500932. The particle collisions and friction generate high voltage, once it gets higher than some 10 - 40 kV, then the X-rays can be formed in vacuum. In air the electrons are slow down by air molecules.Yes, as the lab study of this article says: the plasma flows within/across shock layers heats up and accelerates the fast electrons; which then move through that CONDUCTIVE plasma, NOT through air or other 'neutral' media. So in that situation studied/experimented, the ONLY radiation by fast moving electrons through conductive plasma is most likely synchrotron type radiation as the fast electrons move in 'spiraling paths' within magnetic fields at whatever 'spiral circuit' frequency' applies.
what are the chances of that happening this time, Ira?
Well knowing the can't-Skippy like I do know him, I would say your chances are about zero, maybe less.
@RC, synchrotron radiation comes from synchrotrons. That's why it's called "synchrotron radiation.Yes, that's why any 'spiraling circuit' electron along magnetic field 'lines' is characterized as "Synchrotron" (a specific type of "cyclotron") because of the cycling loop paths followed by charges in whatever 'variable loop diameter' spiraling applies.
Supplementary Table S1 shows that while many of the parameters such as CYCLOTRON frequencies and gyro radii are very different between the laboratory and astrophysical cases, scaled quantities, such as the ratio of gyro radii to skin depth, are conversely fairly similar.
Oh and BTW the cyclotron frequencies refer to the acceleration of the electrons by the solar and cometary plasmas,Yes; and also by magnetic fields arising with/around those plasma flows and around comet stretching from 'stagnation zone' at leading edge, to 'tailing zone' at/behind trailing edge). MY pint was that all these accelerated 'fast' electron 'currents' are swirling around along/across magnetic fields, and so inevitably emit a mixed spectrum of X-rays. And...
bremsstrahlungBremsstrahlung 'label' should ONLY apply to slowing SPEED cases, as originally intended. Its 'generic' use, for cases where NO speed reduction is involved, is misleading. The 'fast' electrons in this case are merely changing direction; ie, non-slowing 'velocity' changes (illustrative analogy: gravitational 'orbital' velocity changes do not necessarily involve 'speed' reduction of satellites).
To make the lab look more like a real comet, I'd like to see an external magnetic field used rather than magnetizing the obstacle in the experiment.Yes, I saw that too. Perhaps they wanted to 'cover all bases', so to speak. Which was prudent in my opinion; since there is 'quite a lot happening' in such 'comets-in-solar-wind' situations; eg:
But @RC, you were claiming the X-rays were synchrotron radiation in the first post on this thread. They're not.I merely point out the known/obvious situation: that the fast electrons do NOT 'stop moving'; they are merely 'redirected' UN-slowed along changed trajectories spiraling around within different mag-fields, that's all. So, unless they are being 'slowed/stopped' (in which case they WOULD emit Bremsstrahlung type X-rays), then they will only be changing direction in their looping paths; and hence MUST emit 'cyclotron/synchrotron' type X-rays.
And in plasmas, those "shocks" behave like double layers and it is the electric fields in those DL's accelerating the electrons.
Definitely less, I can't resist tearing down the dirty snowball nonsense. Besides, it's the low hanging pseudoscience easily picked and cast aside.
So are they/you claiming the fast electrons are 'slowed/stopped', instead of just being 'redirected' UN-slowed?Errrr, I don't think you're getting how this works. The momentum of the charged particles has to change and in fact be reduced for there to be any type of bremsstrahlung, and this includes synchrotron and cyclotron radiation. It's not enough to merely change the direction of their velocity and in fact immaterial. The magnitude of the velocity must change.
@jones, it's very important to note that the source and orientation of the magnetic fields in the real situation and the lab simulation are different enough that there may be some confusion based on which situation the writers of the paper are talking about. This may account for some of the confusion about the bow shock origin of the X-rays.
It's also important to keep in mind that there may be more than one source for the X-rays.
There is only one other source for the X-rays and that's K-transitions after an electron is knocked out of the K-shell of an atom and electrons in higher shells replace it.
The reference in Fig. 5 doesn't say the bremsstrahlung contribution is *always* minimal; it says quite clearly it's minimal *if there are no hot electrons.*
It was a bit of a surprise when they first detected them in '96 at Hyakutake.
In retrospect, it should have been predictable. I guess nobody thought to look, until then.
The x-rays have specific signatures which shows that they come from charge exchange reactions between the solar wind heavy ions, and cometary neutrals
In fact, one of the key science results to come from the Deep Impact experiment is the verification of the CXE mechanism as driving cometary X-ray emission using multiple lines of evidence.
No snowball present.
Hmmm, maybe I misspoke. There is another mechanism for X-ray emission: charge transfer between heavy ions in the solar wind and the neutral cometary atoms in the tail. This is detailed in an old paper (now open access by Wiley at https://agupubs.o...6GL03780 choose the PDF button). This paper is referenced in the Rigby et al paper. Note that the emission zone for this process is some 100,000 km from the nucleus of the comet, however, so these will be relatively easily differentiated from the K-shell and bremsstrahlung processes which are very much closer to the cometary nucleus.
Regarding the Deep Impact mission, I will point out that the direction of the bremsstrahlung is a fairly tight beam, so if the mission didn't fly through it they might have missed this.
Hmmm, maybe I misspoke. There is another mechanism for X-ray emission: charge transfer between heavy ions in the solar wind and the neutral cometary atoms in the tail. This is detailed in an old paper (now open access by Wiley at https://agupubs.o...6GL03780 choose the PDF button).
Why are you linking to ancient photos? Whipple came up with his hypothesis in the 40's
We'd never seen a comet!
Charge exchange is electric discharge, that is one aspect of an electric comet.Why are you linking to ancient photos? Whipple came up with his hypothesis in the 40's
Yep, and that's your model jackass. Nothing changed until the mid-80's when it was falsified. The dirty snowball BS is why no one thought to consider x-rays.We'd never seen a comet!
But that is what the guess states it should look like. Ya know, a prediction. It was an ultimate fail.
Most of the voltage difference between the comet and the solar plasma is taken up in a double layer of charge, called a plasma sheath, that surrounds the comet. When the electrical stress is great enough, the sheath glows and appears as the typical cometary coma and tail. Diffuse electrical discharges occur in the sheath and at the nucleus, radiating a variety of frequencies, including x-rays.
In the electric view, there is no real distinction between a comet and an asteroid, apart from their orbits.
I'm not sure where the photo comes from, but Whipple predicted
CX is not an electrical discharge.
This coming from the guys who claims; the magnetic fields will persist long after the electric current is removed"...LOL
What voltage difference?
None seen. Double layers? Where was this found?
Ever heard of asteroids on elliptical orbits,
And Thornhill never predicted CX
Most of the voltage difference between the comet and the solar plasma is taken up in a double layer of charge, called a plasma sheath, that surrounds the comet. When the electrical stress is great enough, the sheath glows and appears as the typical cometary coma and tail. Diffuse electrical discharges occur in the sheath and at the nucleus, radiating a variety of frequencies, including x-rays.
The bow shocks are double layers, the multiple layers in the coma are double layers. Send the MMS mission to a comet and we'll see what we see.
That last sentence is the one to pay attention to, there is your CX. The plasma sheath he refers to in the first sentence is the coma. Even the basics are above your head.
When the electrical stress is great enough, the sheath glows and appears as the typical cometary coma and tail.
What electrical stress? What the hell is 'electrical stress'?
What electrical stress? What the hell is 'electrical stress'?
Like I said, the basics.
https://en.oxford...c_stress
It's been in the scientific literature/lexicon since the 19th-century. ROTFLMAO! New levels of stupidity are exceeded everyday jonesdumb!
It's been in the scientific literature/lexicon since the 19th-century. ROTFLMAO! New levels of stupidity are exceeded everyday jonesdumb!
it's fine to speculate, and it's fine to be wrong when you speculate. I speculate and am wrong quite often. But I always label it as speculation and I don't come along and attempt to pretend I was "right all along"...Please first go read link: https://phys.org/...644.html
keep in mind as well that comets don't make magnetic fields.I never said they did, DS. I merely pointed out the possible causes of them arising in the SW-impact/stagnation-zone plasma/fast-electron contexts which create their own localized dynamical plasma/charge flow system for the duration of said comets' SW transit times. :)
RealityCheck
Mar 13, 2018Before you two 'get nasty' with each other again....please don't! :)
Anyhow, the X-ray observations mean that 'fast-electron currents' phenomenon arises in all 'plasma flow' situations, as above experimenters confirm (and as I also again recently 'reminded' all).
Moreover, this lab experiment also confirms that the X-rays are emitted ONLY in the presence of MAGNETIC fields; so there is the experimental confirmation of the SYNCHROTRON RADIATION which I and others have always maintained is generated all over the universe by ordinary (and NOT 'exotic' DM etc etc fantasy) processes.
So @jonesdave------and all who've been attacking @cantrive85 et al with the claim that "No synchrotron radiation detected, hence no electric currents etc etc"------will you now cease your 'demands' for proof of SYNCHROTRON; since above experimenters confirmed it does happen due to electric currents arising in all 'plasma flow' situations (as I have said all along).? :)