Where do the Neutrons come from to form the Neutron star?

[maddog]

Maddog I'm trying to understand the workings of how a supernova comes about. If it was that simple, I would be playing tennis right now.

I have been directed to read several different forms of instabilities.

Weibel instability

arXiv.org Search

I found 25 Articles at this link, only a handful even related to "Weibel Instability".

For that matter a Weibel Instability even though associated with Neutron Star (mentioned

in 3 papers I read), they are referring to the plasma around the object and near the

surface. Also this is seen as an "after event" not "before". This lends little creedance

to you thesis that this could "cause" a Supernova. The Definitive answer would be NO! :hihi:

and one paper that I have just read is quite interesting in understanding.

[0904.0096] Weibel instability and associated strong fields in a fully 3D simulation of a relativistic shock

Weibel instability and associated strong fields in a fully 3D simulation of a relativistic shock

Authors: K.-I. Nishikawa, J. Niemiec, P.E. Hardee, M. Medvedev, H. Sol, Y. Mizuno, B. Zhang, M. Pohl, M. Oka, D. H. Hartmann

(Submitted on 1 Apr 2009)

This paper is applying Weibel Instability to Active Galactic Nuclei (AGN) so is about as

off topic as one could get. Not related... ;)

 

I was going to hold off from posting any papers, but! habits are hard to break.

I would hold off in the future. Irrelevant links take away from the topic at hand.

 

maddog

[Pyrotex]

...Its not just the Weibel instability, we need to look at

Filamentation Instability

Bell Instability

Buneman Instability

Oblique Instability

Two-Stream Instability

Flame Instability...

The topic is open for anybody to add to the subject.

Pluto,

the problem here is that YOU are not adding to the subject.

You are still throwing out more things to "look at"--things that, on the surface, have nothing to do with neutron star formation. You just make 'random' comments and ask 'random' questions.

 

You say you are reading these articles. But you give NO indication that you have read them, that you have understood them. You never mention their contents or conclusions in any kind of meaningful context. You aren't even asking relevant questions about neutron star formation or neutron degeneracy.

 

You just spit out 'random' references to technical papers that have certain keywords in their titles or abstracts. I for one do NOT believe that you have read ANY of those articles. Your very next post must demonstrate some working knowledge, some significant understanding, or I'm gonna bring the hammer down on yer punkin head. ;)

[Boof-head]

Neutrons and protons can be viewed as representations of underlying 'forces' in nature.

Gravitational collapse is the least understood process so far, but we know a lot about what happens to stars during the "main sequence"; how white dwarf stars form, and supernova models appear to reflect actual "behavior" out there.

 

White dwarf dynamics is pretty much where to start with the whole neutron-star to black hole thing.

Degeneracy pressure is the limiting factor in how far the star's remaining matter as a white dwarf, can compress (due to gravity). Neutrons decay, at low-energies, into protons + leptons + radiation; however at high energies, the reverse process occurs. This is part of the electroweak dynamic, there is no reason a process is necessarily "irreversible" in any physical theory.

 

The neutrons don't come from anywhere, they start out as protons in a white dwarf that gathers sufficient extra mass so the degeneracy 'breaks' and the reverse of neutron decay can occur in the high-energy stellar object. It turns itself into a neutron star spontaneously.

[Pluto]

G'day boof-head

 

What I'm seeking to understand how and what is the mechanism that turns matter into Neutrons and houses them in the core.

[Boof-head]

Matter doesn't get turned into neutrons, as such; what happens is the inverse of weak decay. Instead of a neutron 'becoming' a proton and some other weak decay products, which neutrons will do spontaneously at low energies, the decay products and protons become neutrons

 

But I'm not really a particle physicist, just a computer geek.

 

If you have a look at the weak force, and how it works differently at different background energies, it might get you closer.

 

Also we don't know or know how to explain a lot of things that we observe "out there", as you may know. This includes some things about white dwarf and neutron star dynamics and plasmas, and of course black holes. The last are implied by theory and indirect observation. Dark matter/energy is the least understood and most indirect kind of astronomy.

[maddog]

The neutrons don't come from anywhere, they start out as protons in a white dwarf that gathers sufficient extra mass so the degeneracy 'breaks' and the reverse of neutron decay can occur in the high-energy stellar object. It turns itself into a neutron star spontaneously.

Not quite right. The mass of the original star that produced a White Dwarf remnant does

not have the mass sufficient to produce degenerate matter (neutrons). The mass of the

original star to produce a Neutron Star needs to be more than 2.1 Solar masses. The

explosion of the Supernova event cause the produce of degenerate matter (remnant core

into neutrons). This is done by implosion of the core caused by equal and opposite impulse of

the explosion.

 

The rest of what you said accurate. The neutrons of the Neutron Star come directly from the core of the original star. They didn't appear through some mysterious process.

 

This has already been explained multiple times in this thread and has been ignored by

Pluto. I personally don't get it... :)

 

maddog

[maddog]

What I'm seeking to understand how and what is the mechanism that turns matter into Neutrons and houses them in the core.

Pluto,

 

This has been posted for multiple time. The answer is here. Since you haven't gotten it

so far, I will lay it at your feet once more: :)

 

From Modest, Post #6

Normal star ---> Neutron star

neutrons, protons, electrons ----> neutrons

 

Where did all the protons and electrons go? They combined and turned into neutrons. To answer your question as directly as possible: the neutrons of a neutron star come from the mass of the parent star. The parent star creates the daughter star, and... that’s where babies come from :)

 

From Sanctus, Post #14

But if the gravitational force is big enough then the electrons degeneracy pressure is not strong enough and it costs less energy to make an inverse beta decay where you have the reaction:

then if the gravitational is not too big it will be this neutron degeneracy pressure which arises now (also neutrons are fermions...) which stops the collapsing of the star and a neutron star is born.

Sanctus even gave you the formula. This is what does it. Finit!

 

From Pyrotex, Post #24

I believe the core does lose mass, in the form of neutrinos.

Several million tons of neutrinos--which is a LOT of neutrinos.

But I really doubt that that is what he is referring to.

These neutrinos are what's in the formula above [sanctus]. That is all there is to it.

 

maddog

[Pyrotex]

Ok, Pluto,

there you have the total set of answers to your question.

That is where the neutrons "come from" in a neutron star.

They were there all along, just in a different form of matter (protons + electrons).

That's it. That's the answer.

Now, please say something appreciative.

[Pluto]

G'da rom the land of ozzzzz

 

Thank you for your informatiion and I agree with you.

 

That information I have and in much more detail.

 

Now the mechanism that I'm trying to understand is experemented with Z-pinch and tokomaks and observed in magnetic reconnection that is responsible for the transients and the production of ultra density Neutrons. I have given this information before.

 

[0903.3968] Reconnection Electric Field and Hardness of X-Ray Emission of Solar Flares

Reconnection Electric Field and Hardness of X-Ray Emission of Solar Flares

 

Authors: Chang Liu, Haimin Wang

(Submitted on 23 Mar 2009)

 

Abstract: Magnetic reconnection is believed to be the prime mechanism to trigger solar flares and accelerate electrons up to energies of MeV. In the classical two-dimensional reconnection model, the separation motion of chromospheric ribbons manifests the successive reconnection that takes place higher up in the corona. Meanwhile, downward traveling energetic electrons bombard the dense chromosphere and create hard X-ray (HXR) emissions, which provide a valuable diagnostic of electron acceleration. Analyses of ribbon dynamics and HXR spectrum have been carried out separately. In this Letter, we report a study of the comparison of reconnection electric field measured from ribbon motion and hardness (spectral index) of X-ray emission derived from X-ray spectrum. Our survey of the maximum average reconnection electric field and the minimum overall spectral index for 13 two-ribbon flares show that they are strongly anti-correlated. The former is also strongly correlated with flare magnitude measured using the peak flux of soft X-ray emissions. These provide strong support for electron acceleration models based on the electric field generated at reconnecting current sheet during flares.

 

 

 

 

[physics/0411167] Research on pinches driven by SPPED 2 generator : hard X-ray and neutron emission in plasma focus configuration

Research on pinches driven by SPPED 2 generator : hard X-ray and neutron emission in plasma focus configuration

 

Authors: Leopoldo Soto, Jose Moreno, Patricio Silva, Gustavo Sylvester, Marcelo Zambra, Cristian Pavez, Veronica Raspa, Fermin Castillo, Walter Kies

(Submitted on 18 Nov 2004)

 

Abstract: SPEED2 is a generator based on Marx technology and was designed in the University of Dusseldorf. SPEED2 consists on 40 +/- Marx modules connected in parallel (4.1 mF equivalent Marx generator capacity, 300 kV, 4 MA in short circuit, 187 kJ, 400 ns rise time, dI/dt~1013 A/s). Currently the SPEED2 is operating at the Comision Chilena de Energia Nuclear, CCHEN, Chile, being the most powerful and energetic device for dense transient plasma in the Southern Hemisphere. Most of the previous works developed in SPEED2 at Dusseldorf were done in a plasma focus configuration for soft X-ray emission and the neutron emission from SPEED2 was not completely studied. The research program at CCHEN considers experiments in different pinch configurations (plasma focus, gas puffed plasma focus, gas embedded Z-pinch, wire arrays) at current of hundred of kiloamperes to mega-amperes, using the SPEED2 generator. The Chilean operation has begun implementing and developing diagnostics in a conventional plasma focus configuration operating in deuterium in order to characterize the neutron emission and the hard X-ray production. Silver activation counters, plastics CR39 and scintillator-photomultiplier detectors are used to characterize the neutron emission. Images of metallic plates with different thickness are obtained on commercial radiographic film, Agfa Curix ST-G2, in order to characterize an effective energy of the hard X-ray outside of the discharge .

 

 

Also

 

3D nonlinear MHD simulations of ultra-low q plasmas

Nov-08

Magnetohydrodynamic (MHD) phenomena occurring in the ultra-low safety factor (ULq) configuration are investigated by means of 3D nonlinear MHD simulations. The ULq configuration, a screw pinch characterized by the edge safety factor qedge in the interval 0 < qedge < 1, is the intermediate state between the tokamak and the reversed field pinch. This numerical study, based on the simple frame of the visco-resistive pressureless MHD model, shows that ULq plasmas have the natural tendency to select discrete qedge values which are about the major rational numbers, suggesting plasma self-organization. Similar behaviour is observed in experimental ULq discharges, like those recently obtained exploiting the flexibility of the RFX-mod device. The transition of qedge from a major rational number to the next one occurs together with the development of a kink deformation of the plasma column, whose stabilization yields a nearly axisymmetric state with a rather flat q profile. Numerical simulations also show that it is possible to sustain either of the two conditions, namely, the saturated kink helical configuration and the axisymmetric one, by forcing qedge at a suitable value. Finally, the effects of this MHD phenomenology on the confinement properties of ULq plasmas are discussed.

 

The above links are just a tip off the ice berg.

 

 

Without gravity the process would not be functional.