Radaition Shielding and Ion Drives

[Aireal]

Radiation Shielding A simple outline

The three main schools of thought on these are: Material Shielding, which has the drawback of mass. A major factor for a ship design. Magnetic Shielding, which is weak points at the poles, much like the Earth does. It also requires a strong magnetic field, which might have its own ill effects, we don't know yet. Electrostatic Shielding, by giving the hull a large positive charge, you can repel cosmic-ray protons. But it creates a bombardment of electrons in the range of its field effect.

The key might be to combine the strengths of each of these methods, while reducing their drawbacks. This can give us a reduction in mass and energy requirements over any stand alone system. Lets start with electrostatic shielding and how it can be improved.

As stated earlier, a section of a ship can be given a charge to repel like charges, but it attracts like charges. Both positive and negative particles are a problem in space. Instead of charging the outside of the hull around the crew where bombardment would be a problem, move the charged areas to the ends of the ship, away from the crew. Use both a positively and a negatively charged region at opposite ends of the ship, perhaps on extensions to increase distance from the crew area. This will draw charged particles away from the area between the poles, reducing the number headed for the crew area. We have in effect turned the ship into a large dipole.

As cosmic radiation bombards the poles of the ship, the charged particles will cause a change in the potential of the dipole we have created. This change in potential will caused the dipole to generate a magnetic field. A magnetic field will also help to deflect cosmic radiation away from the crew area and towards the poles of the ship. As we are using the electrostatic system to generate the magnetic field, there is little to no increase in mass and energy requirements for the added protection. The dipole system could be operated from within the ship to generate a magnetic field instead of depending on the effects of cosmic radiation. I have yet to determine which method would be the most efficient.

Material shielding is last on our list. Its use should be limited to vital areas due to mass. Plastics like polyethylene fit the bill of low mass and good protection. Recent work that allows plastics to carry a charge however can make material shielding even more effective. Charged layers of plastic within the plastic shielding, whose charge does not radiate into space, would help to stop charged particles that penetrate the hulls skin. This will increase the effectiveness of material shielding, allowing less to be used for the same degree of protection. An overall reduction in mass.

So by combining all three shielding concepts into a single design concept, an overall reduction in mass and energy requirements for protection from cosmic radiation can be achieved.


Could Ion Drive technology be the key to radiation shielding, while at the same time improving ion drive efficiency? A deeper look.

The standard ion drive has a stage of operation where it collects excess electrons and injects them into the ion beam to prevent the spacecraft from accumulating a large negative potential.

What if that stage could be eliminated, and the negative potential be used to help shield the crew and equipment. First we must look at the problems of radiation shielding for crews in outer space. The three main schools of thought on these are: Material Shielding, which has the drawback of mass. A major factor for a ship with ion drive. Magnetic Shielding, which is weak at some points, much like the Earth is. It also requires a strong magnetic field of about 20 teslas, which might have its own ill effects, we don't know yet. Electrostatic Shielding, by giving the hull a positive charge of 2 billion volts or so , you can repel cosmic-ray protons. But it creates a bombardment of electrons in the range of its field effect.

The key might be to combine the strengths of each of these, while reducing their drawbacks, with a unique hull concept.

Picture the hull as a giant capacitor, and the ion drive giving it a charge with the electrons that would normally be collected and ejected into the positive ion stream. Each charged layer of the hull would be separated by an insulator material that is also a good radiation shielding material. The most likely bet would be a plastic, or maybe a ceramic. The skin of the hull should have a neutral charge, where as one end of the ship would have a positive charge, and the other a negative, powered by the hull capacitor system. This will generate a magnetic shield around the ship. Now all three of the main shielding systems are in place, let's look at how they interact.

At this time a nuclear electric propulsion (N.E.P.) can deliver power levels of several hundred kilo watts to an ion drive, and may reach the megawatt category in the near future. This means an ion drive could generate a large charge in the hull to create a magnetic shield around the ship. I am not sure what the max. field strength would come to, but most likely not large enough to stop the radiation on its own. The good new is, it does not have to stop it, just redirect a few particles toward the poles of the ship, and slow down the rest.

Once the charged cosmic particles have been slowed down by the magnetic field, they will encounter the hull. Passing through the skin of the outer hull, they will next encounter the material which serves as insulator and shielding. This will slow the particles down even more. Then it will encounter the first charged layer of the hull capacitor system. These charged layers will act as electrostatic shielding within the hull. Then the cosmic particles must repeat the process of going through material and charged layers till it is hopefully stopped. Because our hull has both positive and negative layers in it, it will protect against a greater range of charged particles than the standard electrostatic field design. To a charged particle, this process will act as if the hull was a material shield with electrostatic shields within it, combining these two shielding concepts. As this setup is used to create the magnetic field, all three shielding concepts are now one system. So we now have all three of the main radiation shielding systems in place, all working together. So what are the advantages of this approach, let us look.

The first advantage is an overall reduction in mass needed to protect the crew. Every gram of weight saved in material shielding would be worth its weight in gold for an ion drive ship. With just material shielding alone, it would take about one kilogram of material per square centimeter to protect a crew, that's a lot of mass. Where as magnetic and electrostatic systems have huge energy requirements. By combining the magnetic and electrostatic systems into one, we have already cut the power needed by half. With the system using the potential difference created by the ion drive, the need for its own power supply is reduced or eliminated, another reduction in weight. Because the load of protecting the ship is split between three systems, we do not have to use as much power for magnetic and electrostatic systems as if the were run alone. So the overall energy requirements for the ship is reduced also. Yet every design has some drawbacks, so let's look at how these can be reduced in this system.

Magnetic fields provides little shielding at the poles. As our magnetic field is created by the charged areas at each end of the ship, this problem will be increased from particle bombardment in these regions. The simplest way to solve this is to place the crew area in the center of the ship, away from the poles. Antenna or other extensions from the ship could move the poles even farther away from the crew, for an added measure of safety. As the crew would also need shielding from the reactor, the ship design may look something like this. A long cylinder with a antenna projecting from the front of it, the reactor and ion drive at the rear, with the crew area in the center. Of course other designs are possible with this concept. The standard electrostatic shielding concept has the drawback of causing particle bombardment due to its field radius in space around the ship. By locking these charged areas in the hull with a capacitive design, we limit the range that this field expands into space, thereby reducing the problem of particle bombardment. Next we must pick the shielding/insulator material. As it must fill two jobs, it may take some research to determine the best choices. Plastics like polyethylene might be a good starting point. If a lightweight material for the charged layers could be found, this would help in mass reduction, and make the charged layers better as material shielding. Work is already being done in this area. Adding carbon, graphite or nanotubes to plastics is one approach, polycarbonate might be a good chice for this, as it would add some impact protection also. Interpenetrating Polymer Network ( I.P.N.), and similar work by companies like the Eeonyx Corporation are promising also. Thus we can reduce the disadvantages of each of these systems while taking advantage of their strong points. The next question is, are there any other aspects we need to address with this design concept?

What if the capacitive charge in the hull started climbing too high for some reason? There would need to be a system in place to bleed off excess power and divert it to the ion drive or some other use. In the event of a solar storm, primary power could be diverted to increase the field strength. After the danger has passed, the extra power could be sent to the ion drive. This approach may allow for less than max. protection in the normal state, and protection increased when needed, resulting in an even lighter ship design. Perhaps a Faraday Cage (RF shielding) could be constructed around the crew area to help protect them from the magnetic field effects also. Another area for improvements would be the outer skin of the hull. Could it be made to generate usable power from the constant bombardment of particles. A recent discovery by researchers of the Material Sciences Division of Berkeley and partners show that alloys of indium, gallium, and nitrogen can convert virtually the full spectrum of sunlight, from the near infrared to the far ultraviolet, to electrical current. So even the outer hull of the ship may have more than one use in the future. The hull should be modular in construction and design. This will lessen the chance of system failure if a hull section gets damaged, allow repairs to be conducted in flight, and make construction quicker and more cost effective.

An increase in ion drive efficiency might be obtained by correctly locating the positive pole at the rear of the ship in relation to the ion drive. As the positive ion stream left the ion drive it would encounter the positively charged field at the rear of the ship. The ion stream would be repelled even faster away from the ship, while imparting a slight increase in thrust to the ship. While it may not be much of an increase, every little bit helps over long interstellar trips.

Hopefully this approach would reduce the weight and energy requirement of our spaceship by 2/3 over standard designs, while still protecting the crew and equipment.

I still have a lot of details to work out, but would like some feedback on the basic concept before going much farther. Thank you.

[haselhurst]

Hi Aireal,
Interesting. I have no ideas to add unfortunately. And this forum is mainly for discussing the wave structure of matter (largely unknown) thus it is small and you will not get many replies (if any).
However, there is a smart guy, Mike Harney, who works on the WSM and also is a bit of an inventor (has electronics business). He sent me an article recently on using knowledge of WSM to build radiation shields. Will send him a link to your article, see if he has any thoughts.
Good luck with your ideas.
Geoff

[Aireal]

Haselhurst, My Thanks
Your contacting someone who could make an evaluation of my idea is more help than I could have hoped for. I have had far less luck elsewhere. So I guess I did come to the right place after all. I noticed a thread on how hard it is for independent researchers, ain't it the truth. I am a retired stage hand with too much time on my hands. I have taken many courses over the years, but I only have a 2 year degree, I am mainly self taught. Which does not help when proposing concepts of this complexity.

However I find myself very interested in this forum, though I know little about the wave structure of matter. I will be spending a lot of time here reading no doubt. It may be some time before I post on a subject, but I will be around. I love learning new things. Its a great site.

[haselhurst]

Thanks for being so nice. Greatly appreciated.

I am only just sending email now (hurt my eye chopping wood 2 days ago, have been away from computer).

It seems we share a lot in common - I like people who are curious / creative, and self taught (learning for the right reasons).

I am also convinced that the wave structure of matter provides the correct foundations for describing matter interactions in space, so it should greatly help with your work. But it is very complicated once you have trillions of trillions of waves flowing through one another!

Anyway, just a short reply, hope that we can make some progress.
Cosmos,
Geoff

[mike]

Hi Aireal,

This is a fascinating concept - of using charged layers in the hull to shield the ship. Especially as you mention, there is charge accumulated as the ship travels at high speed through the small grains of dust and Hydrogen atoms.

I have been doing some research on radiation shielding using WSM concepts (see www.signaldisplay.com/electric.html ). My experiments show that gamma sources at 0.5 - 1.0 MeV can be reduced with electric fields due to the nature of the electric field which is really a phase shifted quantum wave (see more on wave centers at spaceandmotion.com). Every wave has to have a frequency and the electron's compton frequency is the most logical - mc^2 = h(frequency) where h = planck's constant. This frequency is exactly in the range of 0.5 - 1.0 MeV gammas. I assume waves travel in the same medium, wich I hope they do - I still don't understand how we got to the current state of physics with just the concept of a field - it means nothing in the physical sense and has caused more confusion for even the great physicists like Newton and Einstein.

For simplicity (and Occam razor's) sake, let's assume all EM waves travel in the same "ether" (the real ether - space fabric that creates mass instead of just stopping at it's boundaries like some imaginary gas). Then waves that cross each other that are reasonably close in wavelength produce intereference patterns (which we measure). Then, gammas at 0.5- 1 MeV get interfered with by high electric fields, and we have a very specialized radiation shield (only for high energy gammas). Now this will not protect agains the high-energy protons you mention, but every little bit helps and further research in this area of WSM and matter-wave interaction might reveal better methods to increase shielding.

I do like your ideas about charged hulls - in fact, I am starting to wonder if we shouldn't do the same with our houses to protect us when the ozone layer disappears!

Regards,

Mike

[haselhurst]

Thanks Mike - great reply - greatly appreciated!
Geoff

[Aireal]

Mike, I found your work very interesting, though I must admit it took me some time to digest it. My math is not the greatest, and I am new to Wave Theory. I was interested in one aspect of your experiment, you noted that the electric field always increased the Geiger counter readings by 2 counts or so. As the wave from the electric field propagates through space could it be creating and/or carrying particles that register this increase. In my research I have noticed that small amounts of radiation have been detected near electric and magnitic fields, but I have never thought about why this is so.

Your experiment has profound implcations for the future of radiation shielding. Forgive my laymans termology, but it seems that it is possiable to cancel out gamma emissions with an electric field in much the same way sound waves can be used to cancel out other sound waves. You also noted in the experiment that there was no decrease in the Rad. count unless radiation was passing through the electric field. This would also support the idea that waves were canceling each other out. Besides the implcations for shielding, this experiment could be the start of valadation for wave theory. I have not crunched any numbers, but it seems to me that the energy density of your electric field was too weak to account for the decrease in rad count except by canceling of the waves.

As for how or why physics uses the concept of a field, I do not see how we arrived at that point. Field lines are arbitary, and do not do a good job of describing field effects. I picture things in my mind, I have found it easier for me to picture waves expanding from a point, much like waves traveling out from a pebble dropped into a pond, only in three dimensions. This was a great help to me in designing my shielding concept, as I could picture how the differant fields would interact. So even though I know little about wave theory, I believe it is vaild as it seems to work on a more intuitive level while still being able to explain the universe in scientific detail. I do not wish to discuss wave theory in detail, as I do not know enough about it to do so in an intelligent manner yet. But the subject has caught my interest, and I will be doing a lot of reading on it for some time to come. I did do some research into Zero Point Energy a number of years ago and I noticed that the concept of waves traveling through an Ether was refered to quite often. So at least at one time the concept of wave theory was in use, but seemed to vanish for some time. Are any of these early theories related to modern wave theory? I will have to look into that I suppose.

Overall I enjoyed your post and your link very much, and they gave me much to think about. Please feel free to share my concept with anyone that may find it usefull or interesting as I do not know anyone that can make use of it. Thanks again.