Plasma Engine

[starbiter]

http://www.space.com/businesstechnology ... 00305.html

[...]


A company founded by former NASA astronaut Franklin Chang-Diaz has been developing a new rocket engine that draws upon electric power and magnetic fields to channel superheated plasma out the back. That stream of plasma generates steady, efficient thrust that uses low amounts of propellant and builds up speed over time.


This seems kind of EU.

[junglelord]

They claim they can reach mars in 40 days, I'm in, lets go.

[jjohnson]

Bring plenty of shielding, JL. Often overlooked is radiation exposure on a long trip like this. The Ad Astra engine should be able to reduce trip time significantly, but it's hot out there. There have been a couple of articles on that subject in Semiscientific American, and the weight of an adequate shielding mass, or the equivalent using electromagnetic shielding is stupefying. We can make MIL-spec radiation hardened circuit boards for our instruments, but it's real hard to radiation harden the passengers! It's like the Jamaica Me Tan tanning salon x 10^12. Whoo-ee!

But having comfortable, steady continuous thrust out to turn-over, and the same to decelerate on in, is a great solution. The specific Impulse rating on that engine is an unbelievable 5000 or so, and it's throttleable, another nice "feature".

Wish 'em luck. They have a contract to install one on the ISS so that it can adjust its orbit without having to get a boost from the Soyuz engine in the docking collar.

[Harry Costas]

G'day

What if I said you could reach Mars in 10 days?

We have at the moment, got the ability to confine plasma but not at extreme densities. Once this is done the sky is the limit.


http://arxiv.org/abs/1001.4480
A first principles explanation for the density limit in magnetized plasmas

Authors: M. Zuin, A. Carati, M. Marino, E. Martines, L. Galgani
(Submitted on 25 Jan 2010 (v1), last revised 1 Feb 2010 (this version, v2))

Abstract: Fusion research on magnetic confinement is confronted with a severe problem concerning the electron densities ne to be used in fusion devices. Indeed, high densities are mandatory for obtaining large efficiencies, whereas it is empirically found that catastrophic disruptive events occur for densities exceeding a maximal one n^M_e. On the other hand, despite the large theoretical work there is no widely accepted, first principles model for the density limit (see [1], abstract). Here, we propose a simple microscopic model of a magnetized plasma suited for a tokamak, for which the existence of a density limit is proven. This property turns out to be a general collective feature of electrodynamics of point charges, which is lost in the continuum approximation. The law we find is n^M_e = 1.74 1/(me c^2) B^2/ \mu_0, (1), where \mu_0 is the vacuum permeability, c the speed of light, me the electron mass, and B the magnetic field. As shown in Fig. 1, the theoretical limit (big circles) is in rather good agreement with the empirical data, actually a surprisingly good one for a model based on first principles, with no adjustable parameter.

That is one way to understand, another way is by breaking down the sub-atomic particles down to the simplest particels forming matter that spins forming a vortex that is able to eject this submatter at the speed of light, the experiments on this are at the door steps.

[junglelord]

No fear of radiation, we went to the moon in a bucket, or did we?

[Harry Costas]

G'day Junglelord

And a shovel.

I may have posted this link before, I think I have.

Dark Matter Axions
00/2010
http://adsabs.harvard.edu/abs/2010IJMPA..25..554S
http://adsabs.harvard.edu/cgi-bin/nph-d ... db_key=PHY

The hypothesis of an 'invisible' axion was made by Misha Shifman and others, approximately thirty years ago. It has turned out to be an unusually fruitful idea, crossing boundaries between particle physics, astrophysics and cosmology. An axion with mass of order 10-5 eV (with large uncertainties) is one of the leading candidates for the dark matter of the universe. It was found recently that dark matter axions thermalize and form a Bose-Einstein condensate (BEC). Because they form a BEC, axions differ from ordinary cold dark matter (CDM) in the non-linear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles. Because there is evidence for these phenomena, unexplained with ordinary CDM, an argument can be made that the dark matter is axions.

Please do not confuse the dark matter/energy with the BBT. This type of dark matter is quite different and lives within condensed matter several times the density of nuclear matter.
The mechanism that provides the spin is most important it allows us to explain the formation of stable jets large and small.

[jjohnson]

Hi, Harry - what do the authors mean by, "It was found recently..." ?

"Finding" has a different meaning depending on the finder, and what a theorist "finds" can be qualitatively different from what an applied astronomer "finds". It's the difference between getting images from an LED array at the focus of an optical telescope and using the absorption energy of electrons of different wavelengths to theorize that an optical system could be made to produce images with the right post-processing. It is "inferring" rather than "observing". Thought process versus external machine process to obtain the result.

Was that effect actually observed in a lab setting? -or was it found mathematically via computing that, by manipulating certain conditions, it appeared that the posited type of dark matter with its posited characterstics (as needed to produce the galactic rotation flatness result, for instance) appeared in that construct or model to be able to form a BEC? If the former, then plausibility starts to rear its ugly li'l head. Otherwise, it's all pretty number theoretical without a noticeable link to reality. At least not yet. I'm keeping the door open, though, and a light on.

Jim

p.s. No 'dim bulb' jokes pls.

[jjohnson]

Okay, I read through the paper, and find that it is made up of a lot of assumptions about axions and how much cold dark matter (CDM) is expected and how it forms the galactic halo of dark matter (inferred, not observed) and so on. Here's a sample:

An important simplification occurs in the case of cold dark matter because CDM particles lie in phase space on a thin 3-dimensional hypersurface. This fact implies that the velocity distribution is everywhere discrete [21] and that there are surfaces in physical space, called caustics, where the density of dark matter is very large.

First, an allegedly 'important' simplification is made, with no rationale supporting why it is important (maybe important to the tractability of their math?).

Next, it is taken as fact (not hypothesized) that the cold dark matter particles lie in phase space on a hypersurface. That may be a good description, mathematically, of a state, but it doesn't say where they actually are in the universe, but then, that may not be relevant.

Then, the alleged 'fact' implies that these axions therefore have discrete velocities (which seems likely to be true of almost any particle velocity - velocities don't come in other flavors (to my limited knowledge) such as evanescent or imaginary, for example, AND that there are discrete "surfaces" called caustics in space where the density of dark matter is very large. I know what caustics are because I've studied focusing effects of sound waves, including sonic boom focusing by aircraft in turns, and by physical devices such as concave surfaces.

My observation here is that this is indeed all hypothetical, because it is based on things which are posited to have occurred with axions in the formation of the Early Universe (setting my bias against this aside). But as axions were admitted in the introductory statements to have never been observed up through the time this paper was written, I consider it possibly may not have happened quite that way, so the bottom card is pulled out from under the house at that point. I would also point out that since neither any sort of dark matter nor axions have been observed (almost by definition) that it would be hard to say that its phase state or any other alleged force or process compresses its energy density into caustics "on a thin 3-dimensional hypersurface" or any place else. This has simply not been observed to occur in the real 'Verse.

Rats. I like good theories. Reading things like this makes me crazy, because their initial postulates mean that, with the possibility of there being a mathematical error, there is no way to falsify this stuff. "It's true because my math shows it is." Well, I'm always as subject to a Black Swan event as the next guy if I don't understand the math correctly, so I'll give it a rest. If we can't falsify this type of theory or hypothetical construct, perhaps we can substitute an alternate or simpler theory and let Occam's Razor do the work for us.

Jim

[junglelord]

I call it brainwashing....maybe disinformation is a good title.

[Harry Costas]

G'day

Its good to think outside the circle.

We are in a subject based on science probability and it will become very interesting in the next few years.

Hello JJ I like your logic.