[Jolly Roger]

Breakable wrote:

…
Nobody has created a DC driven reactive engine, because there was no need for one yet.

.. just not for aircraft, but for rockets ..

That’s what I tried to state.
😛

You did not specify aircraft. And yes, we must not put the cart before the horse. The horse was domesticated as early as 5,600 BC. The wheel was not invented until 3,500 BC, and the cart (chariot) not until 3,200 BC. We are at least 5 years away from getting our horse (5 MW portable electric source). Let’s just hope we don’t have to wait 300 years for our cart.

[Jolly Roger]

(edited)

Aeronaut wrote: Thanx for the links, Jolly Roger. I’d been under the impression that ion thrusters wouldn’t work in the atmosphere.

Technically, the PHP is a plasma thruster, not an ion thruster. Ion thrusters won’t work in the atmosphere because they are high speed, but low thrust. The PHP by itself may not have enough thrust, but in the engine I envision, it is used instead of jet fuel to heat air, which provides the actual thrust.

Think such an engine could do runway to escape velocity?

Maybe. Put liquid N2 tanks where the jet fuel used to be, some injectors in front of the HPH, and we just might have us an honest-to-goodness Space Plane! However, in that configuration we would still be spinning the compressors, which would be a waste of energy at high altitudes. It would be better to install additional thrusters exposed directly to space.

[Jolly Roger]

Breakable wrote: Maybe they don’t have to be propeller-driven?
Nobody has created a DC driven reactive engine, because there was no need for one yet.

To the contrary, such an engine has been created, just not for aircraft, but for rockets – the High Power Helicon (HPH) Plasma Thruster.

http://www.ess.washington.edu/Space/HPH/

http://flux.aps.org/meetings/YR04/DPP04/baps/abs/S2400004.html

http://flux.aps.org/meetings/YR04/DPP04/baps/abs/S810095.html

It has been successfully tested with Nitrogen propellant, so it will probably work with air. The plan would be to replace the combustion chamber of a turbofan jet engine with a large HPH. I strongly recommend the installation of a HEPA filter on the intake, to keep out dust and the occasional CANADIAN GOOSE!!!

[Jolly Roger]

I tried that and it works! Thank you very much.

[Jolly Roger]

Cool! I thought it was something like that. I’ll try it.

[Jolly Roger]

Keep up the good work. I’m sure you’ll figure it out soon.

[Jolly Roger]

I see you are working on it. Thanks for the quick response.

[Jolly Roger]

According to information in the patent application, the maximum net output of each reactor vessel is 5 MW Alpha beam and 2 MW X-rays. With conversion losses, that would be about 5 – 6 MW electricity. However, the capacitor bank, which is the most massive component, can power up to 500 reactor vessels, so total installation output could be as high as 2.5 – 3 GW.

A 2,000 TW application would require 666,667 – 800,000 FF installations.

I will leave it to others with more information to correct mine and/or calculate the mass and volume.

[Jolly Roger]

See my post in the “Can FF take us to the stars?” thread.

[Jolly Roger]

From “DREAD Weapon System” thread:

Brian H wrote:

I never thought of that. But yes, an incredibly powerful focus fusion laser could theoretically be used to accelerate a solar sailing craft to Mars. Or beyond Neptune, Pluto, even beyond the solar system.

I don’t see why you’d bother. Take along a tonne of decaborane and an FF generator or ten, harvest a bit of hydrogen along the way from the interstellar medium, and you could get far more power and acceleration and control and options. With a solar sail, you can’t wander out of the beam or you’re helpless until a signal can be aimed back to the source and the laser re-directed. Braking is tricky, too. You have to pop a counter-mirror out front and turn the sail around to get the bounce-back, or SLT.

You may find this site of interest:

http://www.ess.washington.edu/Space/propulsion.html (Advanced Electric Propulsion)

(minor edit for clarity)

Advanced Electric Propulsion

Chemical rockets have limited application for space applications due to the fact that the fuel is relatively slow (low specific impulse) relative to the speeds needed to move efficiently about the solar system. As a result, chemical systems are massive, and the trip times for missions are very long. Research at UW (University of Washington) in this area is for the development of faster propellants that can provide substantial reductions in cost and trip time. To achieve these efficiencies plasma systems (i..e. charged particles) are required where electric and magnetic fields can be used to accelerate the plasma propellants to speeds more than an order of magnitude faster than can be achieved by chemical rockets. The systems below detail devices under active development:

High Power Helicon (HPH) is an electrodeless plasma thruster that is able run at kW to 100’s kW to produce thruster levels as high as several Newtons (N) of force, at high power and gas efficiency.

Mini-Magnetospheric Plasma Propulsion (M2P2) is a system that can leverage energy from the solar wind to augment the onboard propulsion for spacecraft while minimizing the spacecraft power requires. Potential for radiation shielding is still under investigation.

PlasmaMagnet has the ability to create large magnetic systems without the need for any pre-existing magnets. These systems provide new capabilities for plasma sails and radiation shielding.

MagBeam combines the key features of M2P2 /PlasmaMagnet with high power beam plasma sources such as HPH to produce a system where large orbiting spacecraft can be used to push payloads between the planets with very little cost and thereby facilitate a permanent human presence in space.

(edited)
The MagBeam System is a plasma-magnetic equivalent to the Laser/Solar Sail system above, but has the advantage of being self-aiming, adjustable at the payload, and reversible (push or pull). All the components of the system need power, which Focus Fusion (FF) could provide.

An FF could also serve directly as a plasma source. However, it is probably more useful as the power source of the HPH. Even though FF has a high specific impulse (high velocity), it does not have the high mass throughput, hence Thrust, of an HPH.

BTW, 1 N thrust = ~ 0.1 g acceleration per kilogram of payload. A 100-(metric)ton craft would need about 1,000,000 Newtons (1MN) thrust for 1 g.

NB: M2P2 /PlasmaMagnet can brake at the destination by interacting with a planet’s magnetosphere or a star’s solar wind.

[Jolly Roger]

Tasmodevil44 wrote: There’s no scientific doubt whatsoever that CO2 is indeed a greenhouse gas and contributes to warming. What is still questionable, however, is the fact that there are so many other factors and variables in a more complex equation that can influence the final outcome.

The site I mentioned above states that contributing factors of Global Warming are: solar radiation, volcanoes, solar wind/cosmic rays, El Nino/Southern Oscillation, and human activity (in that order). The “scientific” “consensus” ignores the contribution of solar wind/cosmic rays, even though it is many times larger than El Nino’s, thereby overestimating the contribution of human activity.

Also, CO2 levels are estimated from measurements in Hawaii, which sits in the middle of the Pacific ocean, a major source of natural CO2 out-gassing.

The “consensus” also ignores absorption of man-made CO2 in polar seawater. There is no known difference between the absorption rates of natural and man-made CO2. Its environmental half-life is 3 – 8 years, so if all man-made CO2 production ceased tomorrow, most of it would be absorbed in a few decades, not the centuries the “consensus” would have you believe.

… a super volcano eruption like Yellowstone National Park could still cause an ice age ….

It wouldn’t take Yellowstone. Several Krakatoas could send us into a little ice age.

[Jolly Roger]

Here is an interesting site on the Global Warming controversy.
http://www.rocketscientistsjournal.com/

It takes the stance that the theory of Anthropogenic (manmade) Global Warming is based on bad science.

It is not certain that CO2 is the cause of Global Warming. It may be the other way around.

Millions of years ago, the global temperature was the same, but CO2 levels were 10 times higher. What’s up with that?

[Jolly Roger]

jamini wrote: … in 500 shots a DPF functioning at a peak current of 0.95 MA had neutron yields that had a standard deviation of only about 15%.

What does this have to do with the topic being discussed in this thread, namely a cross-continental tunnel?

[Jolly Roger]

Sorry, but your idea is an old one. NASA’s JPL funded some of Lerner’s research a few years ago.

I found this in the archives:

University of Illinois Space Propulsion
by Admin on Jul 25, 2006 at 09:37 PM
University of Illinois, Air Force Researchers Release Study of Focus Fusion for Space Propulsion.

In a technical paper published last year, researchers from Universe of Illinois and from the Air Force Research Laboratory have described how a dense plasma focus device using hydrogen-boron fuel, (what we call

[Jolly Roger]

JimmyT wrote:
I don’t know how to use the quote thing. Could one of you guys direct me on where to go for instructions on that?

It’s not nuclear science! Just hit the quote button at the bottom of the message you are responding to. It is copied into an edit area. Delete what you don’t want and add new stuff. You can misquote, take things out of context, everything we “pros” do.

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