Thorium fission and Polywell Fusion
Why they are needed and how to get there
Fusion research has been a holy grail of nuclear scientists
for about half a century now; after all the universe is powered by nuclear fusion
in stars. Nuclear fusion is the process by which two nuclei
of atoms of lighter elements collide at very high speeds
and combine to form a nucleus of anatom of a heavier
element. Fusion requires extremely high temperatures,
millions of degrees. It releases the highest amount
of energy per fuel mass among all known physical phenomena.
One may wonder after reading the previous chapter why
fusion research is anymore relevant, once thorium-based
fission is sufficient to secure energy needs in foreseeable
future. There are several reasons to pursue the goal of
fusion reactors, even after thorium-based fission has been
commercialized:
◦ Realizing fusion energy means having a zero-emission reliable energy source, which does not produce any radioactive waste either
◦ Because of its highest theoretical energy production ratio per fuel mass, fusion could potentially enable manufacturing processes which presently require uneconomically high energy input
◦ It is wise to be able to have a choice between fission and fusion technologies as main energy supply
◦ Some fusion technology may turn out to cost just a fraction of fission power's per kWh costs
The diagram illustrates the 'willingness' of
potential fuel types to undergo fusion reaction. The larger
the cross-section, the more willing are fuel particles to
make fusion when colliding head-on. It turns out that
deuterium-tritium (DT) fuel is easiest candidate for
fusion. However, if fusion fuel could be maintained at even
higher temperatures - remember that we are talking about
millions of Celsius equivalent - proton-boron (p+B11)
reaction would become feasible. There are two advantages to
proton-boron fusion, which make it the ultimate design
goal: very low neutron production and easy availability of
both fusion components.
At the start of fusion research, scientists have considered 'inertially confined' fusion, where a spherical electric grid accelerates fuel material into high temperatures towards the center of the sphere. The main problem with this approach is the collision of fuel particles with the accelerating grid, leading to quick evaporation of grid equipment and energy losses outweighing fusion gains. The 'tokamak' concept of ring shaped accelerator has been invented during the 1960s by Andrei Sakharov and Igor Tamm, which does not suffer from grid collision losses. It seemed at the time that developing tokamak fusion is the more fruitful approach, and research on 'inertially confined' fusion has been abandoned altogether, with very few exceptions of some small research groups continuing work on 'inertially confined' fusion as neutron source.
The tokamak uses magnetic fields to manipulate the
deuterium-tritium plasma. Given the extreme technical
challenges of achieving useful fusion rates of even
deuterium-tritium fuels, tokamak researchers cannot dream
at the moment about a more readily available fuel, such as
proton-boron mixture. The distinguishing feature of the
tokamak is its essence of being a “step-down” transformer.
The transformer’s primary is the stack of beige coils in
the center of the tokamak’s torus (in the donut’s hole
below). The transformer’s secondary is the ring of plasma –
the orange skinny donut. An increasing current in the
many-coiled primary induces a much-larger current in the
single-coiled plasma “donut” secondary.
Two magnetic fields combine to produce the resultant magnetic field that spirals helically around the tokamak’s torus (orange skinny donut). This Resultant field contains and controls the plasma. The two magnetic fields that combine vectorially to make the Resultant field are: 1) the toroidal field, generated by the green Toroidal coils; and 2) the poloidal field generated by the orange Plasma Current in the torus. The Vertical coils (the large rings around the outside of the tokamak, and above and below it), can create a vertical magnetic field for controlling the position of the plasma inside the torus. By the laws of electromagnetism, high-energy plasma particles must be tightly orbiting around the spiraling resultant magnetic field lines.
The transformer coils also cause “ohmic” heating in the plasma, which contributes to raising its temperature. However, since the electrical resistance of plasma decreases as its temperature increases, the upper limit on the “ohmic” heating turns out to be about 20-30 million degrees Celsius, which is not high enough for fusion. Thus it is necessary to further increase the temperature by three additional strategies: radio frequency heating, magnetic compression, and neutral beam injection.
During the 40 years of tokamak-based fusion research, the goal of a working fusion reactor seemed always to be 30 years away - it appears to be just as distant today as it has been in the 1960s. With the experience gained through these years, there are numerous reasons to suspect that tokamak-based toroidal fusion would remain elusive for a very long time:
◦ High-pressure toroidal plasma would need to be contained at least on the order of 1 second for a useful output power balance. Magnetically contained high-pressure toroidal plasma appears to be much more unstable than previously thought; erupting local instabilities may also damage the reactor equipment.
◦ The frequent electron-ion and ion-ion collisions cause an even more troublesome result: particle orbits are pushed slightly away from its magnetic field line after each collision, causing a gradual migration towards the containing wall. To keep this particle loss ratio at low levels, it is necessary to increase the distance between the plasma and container walls. As a result, reactor designs are growing larger, decreasing the economic viability of tokamak designs.
◦ The high intensity of neutrons produced in deuterium-tritium fusion quickly corrodes away some parts of the reactor wall.
◦ Tritium is an astronomically expensive and difficult to handle fuel source. Basing economies of scale on such fuel would be problematic.
These are extremely problematic barriers to tokamak viability, and need to be resolved before any deployment prospects of tokamak reactors.
While mainstream scientific community has been focused on the chosen toroidal path of fusion research, some scientists have realized that it could be possible to achieve inertially confined fusion with a 'virtual accelerator grid' of electrons in a plasma sphere. Such arrangement eliminates the problem of ion-grid collisions, which has been plaguing inertially confined fusion in the first place.
The operating principle of such device an electron cloud in the center of a positively charged grid. The grid has strong currents flowing through it, and thereby it becomes magnetically insulated against electrons flying into it. As magnetic field lines flow around the grid, they force electrons to fly along these field lines; i.e. around the grid. Initially, electrons are flying along the green magnetic lines shown on the left side of following diagram. Upon flying out of the grid area symbolized by the hexagon, they are pulled back by electric force of positively charged grid arcs, represented by red dots in the diagram. Electrons are diamagnetic in nature, meaning that their own motion creates a magnetic field which cancels out the applied external field. As shown in the right side of below diagram, a spherical region arises in the center, which is free of magnetic fields due to the motion if electrons. At the edge of this region, magnetic field lines are nearly everywhere parallel to the surface of the sphere - except for small escape holes called 'cusps'. This arrangement of parallel field lines traps electrons at the surface of this central region.
The trapped electrons act as a potential well, attracting and retaining positive charged ions of fusion fuel, which are shot into the center. The following figure illustrates this ion trapping. Ultimately, this central plasma sphere needs to be only slightly negatively over-charged, meaning for example 1 million +1 electron for every 1 million trapped proton. The interior of this plasma sphere arranges itself to be free from both electric and magnetic field lines, with equal number of protons and electrons inside. Essentially, the ions move freely inside the trapping sphere - at least in-between ion-ion and ion-electron collisions - and are returned back from the edge of sphere by electrostatic force of trapped surface electrons. This edge is represented in the following diagram by the location where ion density goes to zero. It still needs experimental verification whether ion densities are peaking inside the trapping sphere as shown on the following diagram - implying very spherical edge surface - or are more evenly distributed inside - implying a bumpy edge surface.
The ions trapped inside this central region consist of readily available protons (i.e. hydrogen ions) and borons (i.e. boron ions). Eventually these ions collide head-on to produce the following energetic fusion reactions.
The occurrence of fusion under described setup has been experimentally demonstrated under the pioneering research of Dr Robert Bussard. The interesting point to observe about this setup is that it remedies all the issue that have been plaguing tokamak fusion research:
◦ It is a stable spherical confinement. The magnetic field lines that are pushed back by trapped electrons are curving towards the center, and tend to restore themselves, applying a balancing pressure to the trapped region.
◦ As electrons are electrically attracted to grid lines, they have no tendency to migrate to the container wall. Some 'up-scattered' electrons are lost as they gather high energy through ion-electron collisions, and need to be replaced by electron guns. But this is a small percentage of electrons.
◦ Proton-boron fusion is neutronless to a very high degree
◦ Both hydrogen and boron are abundantly available, cheap, and practically inexhaustible fuel sources.
The overall arrangement of positively charged
electron containment is shown on the following figure, with
the arrows symbolizing current flows along this grid.
The main loss factor of the system comes from so-called bremsstrahlung radiation. Such energy radiation is produced when energetic electrons and ions collide. In a viable system, energy losses from such electron radiation must be over-powered by produced fusion energy, in other words the brems:fusion ratio must be smaller than 1. It must be also noted that bremsstrahlung radiation is not totally lost system energy, as this radiation is captured on the exterior and can be partially recirculated.
It has been determined that brems:fusion ratio depends on two system parameters: it increases with the growing of average ion charge, and decreases with the growing of ion energies. The first variable can be optimized by keeping more protons than borons in the fuel mixture. Keeping high-energy ions trapped can be ensured by a high density of spherically trapped electrons, which in turn depends on the voltage and current levels of containment grid.
The real challenge is to maintain a high-enough voltage on the positively charged containment grid. High levels of voltage difference can be maintained in total vacuum between the grid and container wall, but the presence of charged ions or neutral gas can cause lightning-like short circuiting between the grid and the wall. Following two strategies are therefore employed for the rector design:
◦ Introduction of electrons and ions through electron and ion guns respectively, so that no neutral gas would be present in the system
◦ Having high electron density in the central trapping region, relative to the regions outside of it. This way ions would bounce back close to the edge of trapping region, and not wander outside of it. The current experimental setup has the escaping ions oscillate radially along magnetic field lines through ring centers, before being returned by the electric force of the grid. A geometric optimization of grid arrangement can improve the ratio of electrons inside and outside the grid area.
One idea for this second point, which still needs to be verified, is to have a grid geometry with strongly recirculating magnetic fields between 'cusp' holes where centrally trapped electrons may escape. That way escaping electrons would not oscillate 'far out' along a nearly radial magnetic field line, but would be kept closer around the grid. In addition, a 'tornado'-type magnetic trap can be applied outside the charged grid, reflecting back any energetic electrons and ions towards the center. Altogether, a very few ions are expected to be between the tornado trap and external container wall, allowing a substantial increase of grid voltage. Such potential arrangement for a next experimental setup is shown in the following diagram. The left picture shows the charged grid, with current arriving in through red wires and exiting through black wires. The right picture shows the grid arrangement within a magnetic tornado trap:
The overall energy production is proportional to at least square power of number of trapped ions. According to research results of M. Ohnishi et al, if ion density can be made to peak significantly in the center of trapping center, fusion production rate is closer to the third power of number of trapped ions. That is a very rapid increase; every doubling of fusion fuel density increases output power density 8 times.
This described concept of inertially confined fusion through a virtual electron grid confinement is commonly referred to as 'polywell fusion', referring to the polygon-like shape of positively charged containment grid. It appears to have been invented by M. Sadowsky in 1969, just a few years after the emergence of tokamak concept. Apparently, the idea got 'lost on the shelf'. Dr Robert Bussard has reinvented it during the 1990s, and has lead a research team working on its experimental validation. Interestingly, a substantial funding for fusion research in USA has been initiated by experts on inertially confined fusion, such as Dr Hirsch and Dr Bussard. Contrary to their expectations, they later saw all research programs exclusively focused on tokamak fusion. Here is Dr Bussard's recollection of that trend:
The current fusion research status is that many
universities have researchers working on some aspect of
tokamak fusion, and an international construction of
industrial-scale experimental tokamak fusion reactor is
underway. This is the ITER project, with over 10 billion
euro budget. The figure shows the ITER reactor design - can
you find the figure representing human scale?
While ITER will conclusively determine whether energy from tokamak fusion is technically feasible with current scientific know-how, it does not make the challenges plaguing tokamak design go away. In other words, even if technical feasibility were to be proven, it does not automatically make tokamak designs practical or economical.
After the recent passing away of Dr Bussard, the research team working on polywell fusion experimentation is lead by Dr Richard Nebel. Dr Nebel's team has managed to produce a more thorough validation of previous polywell fusion results, with Dr Nebel concluding their findings cautiously in an interview:
Currently Dr Nebel's results results are in peer review, and he is awaiting review results before proposing next experimental phase, which is expected to be construction of a 100-MW experimental polywell fusion reactor. There are very few researchers studying the concept of polywell fusion, and not any single research program funding such further investigations.
While it is good news that tokamak fusion research has been given a real chance, some serious questions need to be asked.
When is the time to re-examine whether focusing almost solely on tokamak fusion research is still such a good idea as it seemed in the 1960s? To at least consider the possibility of having made some wrong decisions? Given its solid theoretical foundations, potential benefits, and absence of identified show-stoppers during pioneering experiments, shouldn't fusion research programs take polywell concept at least as seriously as tokamak concept? Some institutions would reply that 'we are also investigating laser ignited fusion'. With all due respect to researchers working on that topic, besides the slightly unstable plasma configuration (tokamak) and plasma constellation lasting on the order of a nanosecond (laser ignited fusion), shouldn't an actually stable and fusion-capable plasma configuration be of great interest?
The present situation of total lack of commitment for continued polywell fusion experimentation and lack of supporting theoretical research clearly calls for citizen activism. As with the case of thorium based fission, citizen activism could bring about urgently needed research and development steps:
1. Computer simulations of plasma dynamics in polywell confinement and expected reactor behavior
2. Construction of experimental polywell fusion reactors and ramping up theoretical research on inertially confined fusion
3. If results of operating experimental reactor validate reliable energy production, and indicate that per kWh costs would be similar or lower than thorium fueled fission reactor costs, most promising experimental reactor design should be selected as basis for factory manufactured polywell fusion reactors.
4. Establishing the industrial process for factory manufacturing of validated polywell fusion reactor design.
The good news is that Dr Nebel estimates that an experimental polywell fusion reactor could be built in 5 years. There is no time to waste however. The decision to build ITER has been made in the mid-1980s, but its construction has actually commenced only 20 years later. We cannot afford anymore for a similarly long and burocratic process, the present situation calls more for Manhattan project-like schedules.
◦ Realizing fusion energy means having a zero-emission reliable energy source, which does not produce any radioactive waste either
◦ Because of its highest theoretical energy production ratio per fuel mass, fusion could potentially enable manufacturing processes which presently require uneconomically high energy input
◦ It is wise to be able to have a choice between fission and fusion technologies as main energy supply
◦ Some fusion technology may turn out to cost just a fraction of fission power's per kWh costs
At the start of fusion research, scientists have considered 'inertially confined' fusion, where a spherical electric grid accelerates fuel material into high temperatures towards the center of the sphere. The main problem with this approach is the collision of fuel particles with the accelerating grid, leading to quick evaporation of grid equipment and energy losses outweighing fusion gains. The 'tokamak' concept of ring shaped accelerator has been invented during the 1960s by Andrei Sakharov and Igor Tamm, which does not suffer from grid collision losses. It seemed at the time that developing tokamak fusion is the more fruitful approach, and research on 'inertially confined' fusion has been abandoned altogether, with very few exceptions of some small research groups continuing work on 'inertially confined' fusion as neutron source.
Two magnetic fields combine to produce the resultant magnetic field that spirals helically around the tokamak’s torus (orange skinny donut). This Resultant field contains and controls the plasma. The two magnetic fields that combine vectorially to make the Resultant field are: 1) the toroidal field, generated by the green Toroidal coils; and 2) the poloidal field generated by the orange Plasma Current in the torus. The Vertical coils (the large rings around the outside of the tokamak, and above and below it), can create a vertical magnetic field for controlling the position of the plasma inside the torus. By the laws of electromagnetism, high-energy plasma particles must be tightly orbiting around the spiraling resultant magnetic field lines.
The transformer coils also cause “ohmic” heating in the plasma, which contributes to raising its temperature. However, since the electrical resistance of plasma decreases as its temperature increases, the upper limit on the “ohmic” heating turns out to be about 20-30 million degrees Celsius, which is not high enough for fusion. Thus it is necessary to further increase the temperature by three additional strategies: radio frequency heating, magnetic compression, and neutral beam injection.
During the 40 years of tokamak-based fusion research, the goal of a working fusion reactor seemed always to be 30 years away - it appears to be just as distant today as it has been in the 1960s. With the experience gained through these years, there are numerous reasons to suspect that tokamak-based toroidal fusion would remain elusive for a very long time:
◦ High-pressure toroidal plasma would need to be contained at least on the order of 1 second for a useful output power balance. Magnetically contained high-pressure toroidal plasma appears to be much more unstable than previously thought; erupting local instabilities may also damage the reactor equipment.
◦ The frequent electron-ion and ion-ion collisions cause an even more troublesome result: particle orbits are pushed slightly away from its magnetic field line after each collision, causing a gradual migration towards the containing wall. To keep this particle loss ratio at low levels, it is necessary to increase the distance between the plasma and container walls. As a result, reactor designs are growing larger, decreasing the economic viability of tokamak designs.
◦ The high intensity of neutrons produced in deuterium-tritium fusion quickly corrodes away some parts of the reactor wall.
◦ Tritium is an astronomically expensive and difficult to handle fuel source. Basing economies of scale on such fuel would be problematic.
These are extremely problematic barriers to tokamak viability, and need to be resolved before any deployment prospects of tokamak reactors.
While mainstream scientific community has been focused on the chosen toroidal path of fusion research, some scientists have realized that it could be possible to achieve inertially confined fusion with a 'virtual accelerator grid' of electrons in a plasma sphere. Such arrangement eliminates the problem of ion-grid collisions, which has been plaguing inertially confined fusion in the first place.
The operating principle of such device an electron cloud in the center of a positively charged grid. The grid has strong currents flowing through it, and thereby it becomes magnetically insulated against electrons flying into it. As magnetic field lines flow around the grid, they force electrons to fly along these field lines; i.e. around the grid. Initially, electrons are flying along the green magnetic lines shown on the left side of following diagram. Upon flying out of the grid area symbolized by the hexagon, they are pulled back by electric force of positively charged grid arcs, represented by red dots in the diagram. Electrons are diamagnetic in nature, meaning that their own motion creates a magnetic field which cancels out the applied external field. As shown in the right side of below diagram, a spherical region arises in the center, which is free of magnetic fields due to the motion if electrons. At the edge of this region, magnetic field lines are nearly everywhere parallel to the surface of the sphere - except for small escape holes called 'cusps'. This arrangement of parallel field lines traps electrons at the surface of this central region.
The trapped electrons act as a potential well, attracting and retaining positive charged ions of fusion fuel, which are shot into the center. The following figure illustrates this ion trapping. Ultimately, this central plasma sphere needs to be only slightly negatively over-charged, meaning for example 1 million +1 electron for every 1 million trapped proton. The interior of this plasma sphere arranges itself to be free from both electric and magnetic field lines, with equal number of protons and electrons inside. Essentially, the ions move freely inside the trapping sphere - at least in-between ion-ion and ion-electron collisions - and are returned back from the edge of sphere by electrostatic force of trapped surface electrons. This edge is represented in the following diagram by the location where ion density goes to zero. It still needs experimental verification whether ion densities are peaking inside the trapping sphere as shown on the following diagram - implying very spherical edge surface - or are more evenly distributed inside - implying a bumpy edge surface.
The ions trapped inside this central region consist of readily available protons (i.e. hydrogen ions) and borons (i.e. boron ions). Eventually these ions collide head-on to produce the following energetic fusion reactions.
The occurrence of fusion under described setup has been experimentally demonstrated under the pioneering research of Dr Robert Bussard. The interesting point to observe about this setup is that it remedies all the issue that have been plaguing tokamak fusion research:
◦ It is a stable spherical confinement. The magnetic field lines that are pushed back by trapped electrons are curving towards the center, and tend to restore themselves, applying a balancing pressure to the trapped region.
◦ As electrons are electrically attracted to grid lines, they have no tendency to migrate to the container wall. Some 'up-scattered' electrons are lost as they gather high energy through ion-electron collisions, and need to be replaced by electron guns. But this is a small percentage of electrons.
◦ Proton-boron fusion is neutronless to a very high degree
◦ Both hydrogen and boron are abundantly available, cheap, and practically inexhaustible fuel sources.
The main loss factor of the system comes from so-called bremsstrahlung radiation. Such energy radiation is produced when energetic electrons and ions collide. In a viable system, energy losses from such electron radiation must be over-powered by produced fusion energy, in other words the brems:fusion ratio must be smaller than 1. It must be also noted that bremsstrahlung radiation is not totally lost system energy, as this radiation is captured on the exterior and can be partially recirculated.
It has been determined that brems:fusion ratio depends on two system parameters: it increases with the growing of average ion charge, and decreases with the growing of ion energies. The first variable can be optimized by keeping more protons than borons in the fuel mixture. Keeping high-energy ions trapped can be ensured by a high density of spherically trapped electrons, which in turn depends on the voltage and current levels of containment grid.
The real challenge is to maintain a high-enough voltage on the positively charged containment grid. High levels of voltage difference can be maintained in total vacuum between the grid and container wall, but the presence of charged ions or neutral gas can cause lightning-like short circuiting between the grid and the wall. Following two strategies are therefore employed for the rector design:
◦ Introduction of electrons and ions through electron and ion guns respectively, so that no neutral gas would be present in the system
◦ Having high electron density in the central trapping region, relative to the regions outside of it. This way ions would bounce back close to the edge of trapping region, and not wander outside of it. The current experimental setup has the escaping ions oscillate radially along magnetic field lines through ring centers, before being returned by the electric force of the grid. A geometric optimization of grid arrangement can improve the ratio of electrons inside and outside the grid area.
One idea for this second point, which still needs to be verified, is to have a grid geometry with strongly recirculating magnetic fields between 'cusp' holes where centrally trapped electrons may escape. That way escaping electrons would not oscillate 'far out' along a nearly radial magnetic field line, but would be kept closer around the grid. In addition, a 'tornado'-type magnetic trap can be applied outside the charged grid, reflecting back any energetic electrons and ions towards the center. Altogether, a very few ions are expected to be between the tornado trap and external container wall, allowing a substantial increase of grid voltage. Such potential arrangement for a next experimental setup is shown in the following diagram. The left picture shows the charged grid, with current arriving in through red wires and exiting through black wires. The right picture shows the grid arrangement within a magnetic tornado trap:
The overall energy production is proportional to at least square power of number of trapped ions. According to research results of M. Ohnishi et al, if ion density can be made to peak significantly in the center of trapping center, fusion production rate is closer to the third power of number of trapped ions. That is a very rapid increase; every doubling of fusion fuel density increases output power density 8 times.
This described concept of inertially confined fusion through a virtual electron grid confinement is commonly referred to as 'polywell fusion', referring to the polygon-like shape of positively charged containment grid. It appears to have been invented by M. Sadowsky in 1969, just a few years after the emergence of tokamak concept. Apparently, the idea got 'lost on the shelf'. Dr Robert Bussard has reinvented it during the 1990s, and has lead a research team working on its experimental validation. Interestingly, a substantial funding for fusion research in USA has been initiated by experts on inertially confined fusion, such as Dr Hirsch and Dr Bussard. Contrary to their expectations, they later saw all research programs exclusively focused on tokamak fusion. Here is Dr Bussard's recollection of that trend:
I was the assistant director of the thermonuclear fusion division of the Atomic Energy Commission from 1971 to 1973 when it was headed by Dr. Robert Hirsch. ...the Arabs and the OPEC business occurred in the early 1970s we decided to capitalize on it and try to raise enough money to get fusion research really moving in the AEC…We went to Congress and created a program that eventually reached something like $800 million dollars a year in 1970 dollars and escalated because we could say, ‘look, if fusion works, you don’t have to keep using oil.’ When we put that through, Dr. Hirsch, myself and Dr. Alvin Trivelpiece, said, ‘Look, let’s get a lot of money to make the National Laboratories feel happy, so they can pursue their own interests at levels they are happy with, and we’ll take 20% off the top and use it to study things that we really know should be done.’ The problem with this approach was that all three of us left within 9 months. The people who inherited the program thought it was all real and thought we should go ahead with magnetic Maxwellian tokamak fusion, and it’s been that way ever since.
While ITER will conclusively determine whether energy from tokamak fusion is technically feasible with current scientific know-how, it does not make the challenges plaguing tokamak design go away. In other words, even if technical feasibility were to be proven, it does not automatically make tokamak designs practical or economical.
After the recent passing away of Dr Bussard, the research team working on polywell fusion experimentation is lead by Dr Richard Nebel. Dr Nebel's team has managed to produce a more thorough validation of previous polywell fusion results, with Dr Nebel concluding their findings cautiously in an interview:
I've been very pleased, frankly, with the sorts of things we've been getting out of it ... The reason that advanced fuels are so hard for conventional fusion machines is that you have to go to high temperatures; high temperatures are difficult on a conventional fusion machine. ... If you look at electrostatics, high temperatures aren't hard. High temperatures are high voltage.
Currently Dr Nebel's results results are in peer review, and he is awaiting review results before proposing next experimental phase, which is expected to be construction of a 100-MW experimental polywell fusion reactor. There are very few researchers studying the concept of polywell fusion, and not any single research program funding such further investigations.
While it is good news that tokamak fusion research has been given a real chance, some serious questions need to be asked.
When is the time to re-examine whether focusing almost solely on tokamak fusion research is still such a good idea as it seemed in the 1960s? To at least consider the possibility of having made some wrong decisions? Given its solid theoretical foundations, potential benefits, and absence of identified show-stoppers during pioneering experiments, shouldn't fusion research programs take polywell concept at least as seriously as tokamak concept? Some institutions would reply that 'we are also investigating laser ignited fusion'. With all due respect to researchers working on that topic, besides the slightly unstable plasma configuration (tokamak) and plasma constellation lasting on the order of a nanosecond (laser ignited fusion), shouldn't an actually stable and fusion-capable plasma configuration be of great interest?
The present situation of total lack of commitment for continued polywell fusion experimentation and lack of supporting theoretical research clearly calls for citizen activism. As with the case of thorium based fission, citizen activism could bring about urgently needed research and development steps:
1. Computer simulations of plasma dynamics in polywell confinement and expected reactor behavior
2. Construction of experimental polywell fusion reactors and ramping up theoretical research on inertially confined fusion
3. If results of operating experimental reactor validate reliable energy production, and indicate that per kWh costs would be similar or lower than thorium fueled fission reactor costs, most promising experimental reactor design should be selected as basis for factory manufactured polywell fusion reactors.
4. Establishing the industrial process for factory manufacturing of validated polywell fusion reactor design.
The good news is that Dr Nebel estimates that an experimental polywell fusion reactor could be built in 5 years. There is no time to waste however. The decision to build ITER has been made in the mid-1980s, but its construction has actually commenced only 20 years later. We cannot afford anymore for a similarly long and burocratic process, the present situation calls more for Manhattan project-like schedules.