What Is A Plasma?

The fact that blood plasma exists in Medicine, should not be confused with the fact that Plasmas exist, that are defined in Physics, and which all matter can be converted to. In short, a Plasma is what becomes of a gas, when its temperature is too hot, for it to be a gas.

The long form of the answer is a bit more complex. In Elementary School, Students are taught that there exist three familiar phases of a given substance: Solid, Liquid and Gas. But according to slightly more advanced knowledge in Physics, there is no real guarantee, that there will always be these three phases. A gas first results when the thermal agitation between molecules becomes stronger – i.e. their temperature hotter – than the force that holds individual molecules together. At that point, the molecules separate and a gas results, the physical behavior of which is approximately what one would obtain, if a swarm of particles was to exist through collisions but through few other interactions.

Similarly, Liquids will form, when the molecules are forced from occupying fixed positions, but when they still don’t expand.

Well, as the degree of thermal agitation (of a Gas) is increased further, first, molecules become separated into atoms, and then, the electrons get separated from their nuclei, as a result of ordinary collisions with other atoms. This results in the negative particles – electrons – following different trajectories than the positive particles – the nuclei. And the result of that is that the collective behavior of the fluid changes, from that of a gas.

When a charged particle crosses the lines of force, of a magnetic field, a force is generated which is perpendicular to both the velocity vector and the magnetic field vector. As a result, the particles can travel without restriction along the lines of magnetic force, but their motion at right angles to it is deflected, and becomes helical. Not only that, but the direction in which the paths of the particles becomes curved, is opposite for the negative and positive particles.

For this reason, Plasmas can be confined by magnetic fields, except along the lines of the magnetic field. Increasing the strength of an applied field will also cause a Plasma to become compressed, as these helices become narrower.

A good natural example of this type of Plasma, is what becomes of the substance of the Sun. Its temperatures are easily hot enough to cause the transition from Gas to Plasma, especially since the temperature inside the Sun is much higher, than the temperatures which are observed at its surface. At 5000K, gasses are still possible. But at hundreds of thousands Kelvin, or at a Million degrees Kelvin, the bulk of the Sun’s substance becomes a Plasma.

Now, if the reader is a skeptic, who has trouble believing that ‘other phases’ can exist, than Solid, Liquid and Gas, there is an example that takes place at lower temperatures, and that involves Oxygen, namely, O2. We’re aware of gaseous O2 as well as liquid O2 that gets used in rocketry. But as the O2 is cooled further, to 54.36K at 1 atmosphere, it solidifies. Thus, it has already demonstrated the 3 phases which we’re taught about in Elementary School. But, if we cool already-solid O2 below an even lower temperature, 43.8K at 1 atmosphere, its phase changes again, into yet another phase, which is also a solid one. It’s currently understood that solid O2 has 6 phases. (:1)

At the same time, many fluids are known to exhibit Supercritical Behavior, which is most commonly, a behavior of a fluid which is normally differentiated between Liquid and Gaseous, losing this differentiation, due to its critical pressure being exceeded, but at temperatures at which fluids are commonly boiled. This has nothing to do with Plasmas, but without any distinction between Liquid and Gaseous, a substance which is ordinarily though to have three phases – such as water – ends up demonstrating only two: Fluid and Non-Fluid.

So there is no ultimate reason for which matter needs to be in one out of three phases.

(Updated 10/14/2018, 10h25 … )

Continue reading What Is A Plasma?

Black Holes Again

One of the subjects which is subject to controversy these days, is to what extent a real black hole may (not) have any features.

Certain principles in Physics are thought to be stronger, than the existence of black holes. One of those is ‘conservation of momentum’, and another is ‘conservation of charge’. Conservation of momentum already implies, that a black hole is capable of having spin, because the environment could act on it over time, exerting torque. Conservation of charge is often overlooked.

If for some reason, a black hole was to end up capturing electrons in disproportion to how many protons it captures, then what should also happen is that it should build up negative charge. This idea might cause some laughter, but the result of such a scenario would nevertheless follow.

What can be even harder to foresee, is what would happen if the black hole both had considerable charge, as well as spin. According to general principles in Physics, this would imply a ‘convection current’, and then such a black hole should also have a magnetic field.

Only, until recently it was thought that both the amount of charge-imbalance in captured matter, as well as the rate of spin, should be quite small. It was only a recent estimate I heard of, that the rate of spin was in some cases 1/3 the speed of light !!

Also, it has been proposed that there is an ‘energy jet’ which black holes emit. This energy jet might form from the accretion disk, because a strong magnetic field will generally tend to do two things to a plasma: It will compress a plasma, and it will generally tend to force its path of motion, to follow the lines of force, of the magnetic field. The latter is true, because the individual ionized particle do not travel in straight lines, instead traveling in helical paths, that are curved by an applied magnetic field. The helical paths which charged particles follow, will tend to rotate around the axis of the field, but will extend along its axis.

Well nobody has yet answered, whether the ‘energy jet’ from a black hole, initially consists mostly of protons, or of electrons and protons in a perfectly balanced way… If it was to consist mostly of the more massive protons, then the black hole and its surrounding phenomena should also become increasingly negatively charged… I do not actually visualize, the energy jet from a black hole consisting greatly of electrons…

Dirk