 |
| With apologies to Startrek. But this will really fly. |
See the two articles below and make the imaginative leap!
https://www.newscientist.com/issue/3402/
...and here is how my Space Chimney works:
The Citizens
were herded to a circular seating area with viewing screens.
“Very briefly” announced a young woman who had taken over from Samba who was now fifty yards away huddled with a group around bafflingly complex control panels, “…I’ll give you an outline of the flight we’re taking together and – very, very briefly – how The Queen works.”
As she started speaking the clearest pictures they had yet experienced flashed up on the guests’ inner PC screens – and on the display screens.
“…The Queen is solar powered. Powered by starlight. Every square centimetre of surface absorbs light, the electromagnetic field, and converts it to electricity…”
Illustrations of light being captured by solar cells converting at eighty-two percent efficiency accompanied the lecture.
“…the craft is a Space-Chimney… For the Concorde Survivor’s understanding I’ll describe it…”
EmmSon nodded at Sebastian, confirming that he was right and Sebastian wrong.
“…The rim of the Queen spins on frictionless vacuum bearings at sixty-thousand kilometres a second…”
The illustration showed the fat outside rim starting to rotate and getting up to speed so rapidly that it moved faster then the eye could follow and became a blur.
“In the atmosphere, with variable geometry blades, it acts like a helicopter wing. The rotation lifts the Queen upwards – not of course strong enough to get her off the ground at any speed, but you’ll see its ability to effectively make the craft weightless and lift it in Earth’s lower atmosphere…”
Complicated wind tunnel tests showed the rim sprouting short turbine blades and spinning in smoky spirals, which any flight engineer would recognise as evidencing lift. Joe was interested to see that the Citizens were fascinated. They obviously hadn’t seen this before.
The young woman continued at a fast pace “…The rim is also the main space drive – when we switch the chimney on…”
“…on the top of the rim are laser beams placed close together so that when its rotating a seamless column of coherent light – the chimney – beams upwards…”
A graphic of a disk with separate lights at its rim shining fiercely out into space was flashed on screen.
“…The beams are magnetically polarised to attract all and any particles within the chimney to the “walls” of light. This creates an internal vacuum relative to the external pressure and the chimney effect is created.”
“…under The Queen, the rim has lasers that form a cone of light which is polarised the opposite way – to attract particles making the zone beneath the ship of a higher pressure than the ambient external pressure – and far higher than the vacuum in the chimney above.”
“The Chimney reaches out without losing its focus or polarity for a quarter of a million miles. So the “top” of the chimney is about as far away as the Moon. Any questions so far?” she challenged her audience, impatient to get this over with. No-one dared to delay the presentation.
“Good!”
“…Hence the concept of a smoke-stack chimney which joins the high pressure ground air with the lower pressure air at its top, creating an upward flow. Burning fuel at the bottom increases the flow as the warmed air is less dense. The Queen’s lasers do the same job but instead of air flow, what sits in the chimney is the space-craft itself…”
She surveyed her small audience waiting, impatiently, for the penny to drop. She made minute hand movements indicating they should as soon as possible, as soon as their limited intellects caught up, see the point. All around them people were bustling and making ready – and she, a co-pilot, was anxious to get to her station.
“Ah!” rejoined David AA, to everyone’s relief, “The Queen herself is equivalent to the airflow and rises up the chimney…” “Low pressure above and high below… But…” he added with some bravery as their rapid fire tutor was not inviting any detours, “…how do you steer it? The Queen, doesn’t it just go straight up The …Chimney … In Smoke… as it were?” and he grinned sheepishly in case he had asked a totally dumb question.
His momentary fear was quickly alleviated, “Good question…” she praised him – and more graphics flashed onto the screens, “A very good question. Now you see why The Queen is saucer shaped. We point the laser-chimney at our destination, which can be near or far. Wherever we point the lasers, the craft must follow…”
David AA looked pleased with himself and all his colleagues gave themselves a pat on the back for concentration and alertness.
“…The Queen has to be shaped so that when the laser-chimney is fired at an acute angle it doesn’t intersect the ship’s superstructure – otherwise BOOM! It would disintegrate all the particles within the chimney – and end of story! end of us all and end of The Queen. …So its saucer shaped.”
Sebastian smiled triumphantly at EmmSon in an utterly childish “I-told-you-so” retaliation.
“…And finally,” said the young tutor already moving away from them “…once in the chimney we are subject to constant acceleration – so, as Einstein figured out, we get gravity beneath our feet…until we decelerate. When we approach a planet, we reverse the polarities above and below; and it slows us down. Now I really must go. Enjoy your flight – see you later.”
Though the latter was so obviously not her intention they ignored it.
EmmSon, less cowed than the rest by this fast talking, dismissive informant, called after her “But – hey! Hey Miss – But where are we going?”
She stopped and turned, with a look which would make a lesser man tremble. This co-pilot was not to be trifled with. Without taking a single step back to them she flashed up a diagram on the screens, “There. We’re going there. And then we’re coming back again – all in thirty-six hours… …If we ever get off the ground” she admonished. “Got it?”
Plasmas could be used to make the world's most powerful laser
Because plasma can shape very intense light without being damaged, it could be used to make components for lasers thousands of times more powerful than the strongest ones that exist
Laser beams could be more powerful when passed through plasma gratings
Shutterstock/luchschenF
Using plasma to make lasers could make them more powerful and more compact.
Matthew Edwards and Pierre Michel at Lawrence Livermore National Laboratory in California proposed a laser design that includes components made from plasma, a state of matter similar to a hot “soup” of charged particles. They calculated that because plasma can reflect and focus very intense light without being damaged by it, this method could help build lasers thousands of times more powerful than the strongest ones that currently exist.
“We want lasers that can deliver a lot of light intensity, which allows us to do a lot of new, interesting physics. The problem is that as lasers produce more and more power, they have a tendency to destroy themselves,” says Edwards. “But we can put a lot more light on a plasma without damaging it, anywhere from 100 times to as much as a million times.”
The researchers mathematically modelled a laser where a component called a transmission grating, usually made of glass-like materials such as silica coated in gold, would instead be created by shooting smaller lasers into gas to make a specially patterned plasma. Like conventional lasers, lenses and mirrors would help produce a beam of light, but passing the beam through the plasma grating would turn it into a very quick and intense pulse of light.
The power and size of a laser are determined by the ability of the device’s components to withstand a beam’s intensity without breaking, says Edwards.
The most powerful existing lasers require metre-sized transmission gratings and can output tens of petawatts of power over a quadrillionth of a second. If sustained for an hour, this would output more than twice as much energy as the whole US electric grid’s hourly power usage. Edwards says the plasma lasers could produce equally powerful beams with plasma gratings only 1.5 millimetres in diameter. Using even larger gratings could lead to the creation of unprecedentedly powerful lasers.
David Turnbull at the University of Rochester in New York says that the new design is compelling, but that controlling and confining plasma inside of a device is an engineering challenge. However, he says, the design presents an opportunity to push the frontier of laser power and intensity forward, maybe even as far as being able to “rip” empty space into pairs of particles and anti-particles with very intense laser pulses.
Edwards says that though some plasma gratings have been created in experiments, building a whole laser around one will probably take more than a few years. In the short term, the researchers are aiming to test their design by building a smaller but equally powerful version of existing high-intensity lasers.
Journal reference: Physical Review Applied, DOI: 10.1103/PhysRevApplied.18.024026
More on these topics:
Anti-laser can make any object suck in light
A maze of mirrors and lenses turns any material into a highly efficient light absorber and could be used for detection of faint light or charging distant devices with light
A new anti-laser device uses mirrors and lenses to turn any object into a highly efficient light absorber.
Omri Haim, The Hebrew University of Jerusalem
Inserting any material into a special maze of mirrors and lenses can make it absorb light perfectly. This approach could be used to detect faint starlight or for charging faraway devices with lasers.
Ori Katz at the Hebrew University of Jerusalem in Israel and his colleagues created an almost perfect absorber of light by building an “anti-laser”.
In a laser, light bounces between mirrors until it becomes amplified enough to exit the device in a concentrated beam. In an “anti-laser”, says co-author Stefan Rotter at Vienna University of Technology in Austria, light enters the device then gets stuck in an inescapable series of bounces within it.
The researchers achieved this by directing red light through a metre-long maze of carefully arranged lenses, mirrors and one piece of tinted glass. The glass was the intended light absorber. Light reflected off the mirrors and interacted with images of itself created by the lenses in such a way that it got redirected every time it came close to exiting the device.
Before it was inserted in the device, the glass could absorb 15 per cent of light. The whole device, in contrast, absorbed about 98 per cent of the light that entered it, effectively increasing light absorption of the glass more than six-fold.
Sahin Ozdemir at Pennsylvania State University says that, previously, similar devices perfectly absorbed only specific light wave shapes and only when they were illuminated at particular angles. The new “anti-laser” works for all shapes and angles, so it is much more practical, he says.
Ozdemir says that the method could be used to collect light from very faint stars. It could also be used for efficiently charging bigger devices with the energy of absorbed light, like charging a drone by hitting it with a laser from a distance, says Katz.
However, Yidong Chong at Nanyang Technological University in Singapore says that the device may have to be miniaturised and integrated onto a chip before it can be incorporated into useful devices. Currently, the maze of instruments sprawls across a laboratory table, so it is larger than some devices like drones, and vulnerable to lenses or mirrors accidentally being knocked over.
Rotter says that in addition to making the device smaller, the team wants to boost its versatility even further by making it absorb light of many colours simultaneously with near perfection.
Journal reference: Science, DOI: 10.1126/science.abq8103
More on these topics:
No comments:
Post a Comment