Is there a limit to how dense an object can be? “….maybe there are no limits to density!”
Explaining a mysterious barrier to fusion known as the 'density limit' ..... For more than 50 years physicists have puzzled over a daunting mystery: Why do tokamak plasmas spiral apart when reaching a certain maximum density and halt fusion reactions? This "density limit" serves as a barrier that prevents tokamaks from operating at peak efficiency, and understanding what sets this maximum density would speed the development of fusion as a safe, clean and abundant energy source. Recently, researchers at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have revisited an old idea: bubbles called magnetic islands.
Daring move for first US-China fusion team by Staff Writers, Washington DC (SPX) Nov 13, 2015. The way to increase the power and efficiency of magnetic fusion energy may be to risk running the plasma - hotter than 100-million-degrees C - closer than ever to the wall...
Computers uncover mechanism that stabilizes plasma within tokamaks A team of physicists led by Stephen Jardin of the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) has discovered a mechanism that prevents the electrical current flowing through fusion plasma from repeatedly peaking and crashing. This behavior is known as a "sawtooth cycle" and can cause instabilities within the plasma's core.
New Super H-mode regime could greatly increase fusion power 100 million degrees Centigrade. His surprising discovery was that a model called EPED predicted more than one type of edge region in tokamak plasmas, with the previously unknown Super H-mode among them. Such regions are called "pedestals" because they serve as ledges in H-mode plasmas from which the pressure drops off sharply. The higher and wider the pedestal the greater the density and pressure, which together act like thermoses to contain the man-made plasma at more than 100 million degrees C.
Fundamentally Speaking........ tokamaks
Variables to the theoretical density limit suggest unification/integration, common denominators, with equivalent energy differential reference frame substitutions, allowing for measurement through the micro, meso, macro CURVE variations of space and time utilizing the sine wave curve of radius C positions between specified points.
NIF is also in the fusion fray
One such study Density limit in a ﬁrst principles model of a magnetized plasma in the Debye–Hu¨ckel approximationappears to be taking a more integrated variable approach: Lorentz force, Coulomb force, velocity, magnetic ﬁeld, absolute temperature, kB the Boltzmann constant, the discrete nature of matter, the contribution of the ions, the boundary eﬀects, and the inhomogeneities of the macroscopic quantities characterizing the plasma, such as temperature, magnetic ﬁeld and density. More in general, one should consider relativistic eﬀects (the constant C), i.e., the retardation of the ﬁelds, and thus emission of radiation.
where nG is the density in 1020 m-3, Ip the plasma current in MA, and a the minor radius in m.
In tokamaks (and Reversed Field Pinches), exceeding the Greenwald limit typically leads to a disruption, although sometimes the limit can be crossed without deleterious effects (especially with peaked density profiles). Stellarators can typically exceed the Greenwald limit by factors of 2 to 5, or more (replacing Ip by an equivalent current corresponding to the magnetic field).
The mechanism behind this phenomenological limit is not fully understood, but probably associated with edge gradient limits. Recently, an explanation based on the formation of magnetic islands was
However, for what concerns the analytical side of the problem, in order to produce more exact ﬁts with the experimental data one should push the theory much more forward. First one should settle the problem of the contribution of the ions, and include sustainment in the model. Then one should consider the boundary eﬀects, and the inhomogeneities of the macroscopic quantities characterizing the plasma, such as temperature, magnetic ﬁeld and density. More in general, one should consider relativistic eﬀects, i.e., the retardations of the ﬁelds, and thus emission of radiation. Furthermore, one should consider higher order perturbation eﬀects, going beyond the Debye–Hu¨ckel approximation. Useful information on all these problems should also be obtained through numerical studies, along the lines for example of the recent work  on strongly coupled plasmas.
We will show that this leads to a theoretical electron density limit ne given by the law
ne = 3
where B is the magnetic ﬁeld, µ0 the vacuum permeability, c the speed of light and m the electron mass. Using ne = 1/a3 where a is the mean interelectron distance, relation (1) can also be put in the particularly expressive form
mc2 , (2)
according to which the transition from order to chaos occurs when the magnetic energy inside a cell of volume a3 = 1/ne just equals (apart from a factor 1/6) the electron rest energy mc2. We will show below that the theoretical formula (1) ﬁts not too badly the phenomenological density limit for plasma collapses in a large set of fusion devices, and this suggests that the contributions of the ions, which we have here neglected, should be of the same order of magnitude as that of the electrons. This conjecture is supported by a further result, which will be published elsewhere (see  for the case of a smeared out background). Namely, one can discuss the stability properties of the equilibrium solutions of a neutral system of electrons and ions in a constant magnetic ﬁeld, and one ﬁnds a bifurcation to an unstable solution, at a critical density which is the same as (1) apart from a factor of order one.
The Sun (macro) is a massive atomic furnace that works by converting hydrogen into helium. Hydrogen is the lightest and most abundant element in the universe. It has one proton in its nucleus. Temperatures and densities in the centre of the Sun are so great, 1.5 million°C and around 200 billion atmospheres, that colliding hydrogen nuclei sometimes fuse into helium nuclei. The creation of each helium nucleus requires four hydrogen nuclei.
Figure 1 - Extreme ultraviolet imaging telescope image of the Sun.
From SOHO project (http://sohowww.nascom.nasa.gov/)
From SOHO project (http://sohowww.nascom.nasa.gov/)
One helium nucleus has 99.3% of the weight of four hydrogen nuclei. This excess 0.7% of hydrogen mass compared with helium mass is converted into energy. In perspective, the Sun converts 600 million tons of hydrogen into 596 million tons of helium every second. The extra 4 million tons is converted into energy - in this case radiation in the form of gamma rays.
Figure 2 - The fusion (micro) of four hydrogen nuclei to form one nuclei of helium.
You can imagine the enormity of the energy generated when you realise that, given Albert Einstein's famous equation E=MC2, the 4 million ton differential is multiplied by the speed of light, squared. This energy is so great that the Sun gives off 6200 watts of light from every square centimetre of its surface. Compare this to a 60-100 Watt domestic light globe. As far as we know, the Sun has been giving off this light steadily for the last 4.5 billion years,
Here is How
A more refined view of E=MC2 discloses Light (C) as The Radius of Curvature of All Natural Law, equating to the kinetic energy equivalent of the mass energy of matter
meaning if a differential of energy equal to this quantity exists between the observer and the point which he is observing, the natural laws will be suspended. If the energy differential is in excess of the quantity C, the laws will appear to operate in reverse at that point.
The far more fundamental and simpler definitions of space time mass matter energy gravity become mandatory:
- The Quantity C: Possessing a Significance Far Greater than Attributed
- Gravity – As Viewed Through the Radius (VC)
- Space as Observed through the Curve of Radius Light
- Matter and Mass – Quantum Gravity and the Holographic Mass
- Beyond A Uni-Dimensional Perception of TIME
- The Nonlinearity of Physical Law