The military-industrial scientific research system of the academic master.

Chapter 1382 Odd Symmetric Configuration

In order to carry out this closed-loop nuclear magnetohydrodynamic power generation verification plan, Factory 504 deployed a server with very powerful performance in advance.

As a result, the equipment has been put into use before the official renovation project has even started...

Later in the day.

As Chang Haonan's fingers rapidly tapped on the keyboard, the three-dimensional magnetic field model simulated on the screen continued to distort and reorganize as the parameters were adjusted.

Of course, magnetic lines of force do not really exist, but even the most professional researchers have to admit that they are simple and intuitive.

In the control room next door, the young engineer held his breath and watched the red alarm sign flash repeatedly at a critical value.

"Reduce the current of the fifth and eighth coils to 85% of the rated value."

Chang Haonan suddenly spoke, his eyes still fixed on the magnetic footprint map displayed on the screen.

The operator immediately executed the command, and the originally turbulent magnetic field waveform calmed down slightly, but the dark red abnormal area was still faintly visible at the edge of the disk power generation channel.

"Lowering the magnetic induction intensity will alleviate the disorder of the magnetic field topology... But this is the obvious part, nothing has changed in essence..."

He shook his head to himself.

The atmosphere in the room fell silent again.

Han Chenfeng walked in from the door at this time, holding a laptop in his hand:

"Academician Chang, I rechecked the coil assembly parameters and found that the yoke frame has an assembly error of about 10 microns."

He then called up two sets of comparative data:

"When we designed it before, we considered that the effect on the static magnetic field could be ignored. But if we simulate it according to the dynamic disturbance, the asymmetry will be amplified by the resonance...about two to three orders of magnitude."

Although he didn't continue, his meaning was clear.

However, Chang Haonan shook his head decisively:
"Not to mention the cost and tolerance issues brought about by further improving the installation accuracy, the two to three orders of magnitude amplification level sounds scary, but in reality it is only less than one ten-thousandth of the magnetic field position accuracy, and it will not be the root cause of the disorder of the magnetic field topological structure."

Things like electromagnetic devices are indeed very precise.

But this precision is often not reflected in the mechanical precision visible to the naked eye.

For example, in the recently launched International Thermonuclear Experimental Reactor (ITER), the allowable error in the installation of permanent magnets is even sub-millimeter or even millimeter level, and it will not cause any obvious interference.

Such exaggerated changes in the magnetic field structure before our eyes must be due to something going wrong in the electromagnetic conversion process itself.

"Academician Chang!"

At this time, the laboratory door was suddenly pushed open, and Peng Juexian strode in carrying an oily work suit:
"The resonance disturbance spectrum and Poincare map you requested have been produced. I also checked the harmonic interference of the factory's backup power supply and found that it has no correlation with the magnetic field disturbance frequency."

Chang Haonan didn't care about the latter news at all.

The harmonic interference of irrelevant power sources leading to magnetic field disorder can almost be regarded as a metaphysical concept, which is equivalent to the source of electric energy affecting the sound quality of headphones. The reason why Peng Jue was asked to check it first was that since he was already here, he might as well try his best.

The key is the first half.

"Open the resonance perturbation spectrum first!"

Chang Haonan gave orders in the direction of the control room next door.

Soon, a blue and green energy map with a structure somewhat similar to an alien face appeared on the big screen.

"..."

He glanced at the system interface that was still sounding the alarm, and suddenly reached out and pressed the emergency brake button.

As the low buzzing sound gradually weakened, the row of warning lights on the system interface went out or turned back to green one by one.

Peng Juexian's eyelids jumped when he saw this action:
"Academician Chang, a sudden interruption of plasma flow will lead to..."

"It will damage the iridium alloy electrodes worth eight million. I know that."

Chang Haonan said calmly:

"But this cost is still manageable compared to allowing the random layer to expand to the point of destroying the cavity itself."

Then, he pointed to the dark blue patches in the upper left and right corners of the screen:

"See? The area where the Chirikov factor exceeds 0.8 already occupies 17% of the channel cross section."

This time, not only Peng Juexian, but even Han Chenfeng who was half a step behind was shocked:
"Ok?"

The Chirikov factor is not a data that is directly displayed on the image, but requires a little secondary processing.

The "slightest" here refers to computers. It is a bit exaggerated for the human brain to make a judgment in such a short time.

Of course, in reality, if it weren't for the system's reminder, Chang Haonan would not have noticed this problem in the first place. But this matter couldn't be explained in detail, so he quickly returned to the previous topic:

"You see, the strongest part of the perturbation spectrum coincides with the equilibrium magnetic surface. Theoretically, strong resonance means that the resonant magnetic surface will be subjected to greater radial perturbations, resulting in an increase in the width of the magnetic island, thus generating a larger Chirikov factor and a larger width of the random layer..."

Sure enough, everyone's attention followed him and turned their attention back to the screen.

But Chang Haonan spoke very quickly, and the content of his description was a bit abrupt, so no one could react for a while.

Only Peng Juexian came to his senses a little:

"It means... the magnetic field lines can connect the upper outer divertor target plate with the plasma region, causing a large number of particles to directly bombard the upper divertor and trigger the alarm?"

This is still a description of the phenomenon rather than an analysis of the root causes.

Fortunately, the equipment has been suspended, so there is no need to rush.

"Now call up the Poincare map of the magnetic field topology. I guess we should be able to find some magnetic island chains closer to the plasma core, and near point X on the boundary, a strip-shaped epitaxial structure will be formed where stable and unstable manifolds intersect each other... maybe similar to a squashed hexagram."

At this point, Chang Haonan turned his head with a smile and said half-jokingly:
"Anyone want to make a bet?"

In fact, everyone was still skeptical about his description.

But let's stand up and make a bet.

Indeed, no one responded.

Let’s not talk about what to bet on first.

If I lose, wouldn’t that be embarrassing?

And if I win, it will bring shame to my leader, and how can I get anything good out of it?

In order to avoid a dull atmosphere, the operator sitting outside the door quickly called out the Poincare map that Chang Haonan requested.

"Oh~"

A low cry of surprise suddenly rang out from the crowd.

The line pattern shown in the picture is almost exactly the same as what Chang Haonan said.

Although due to the setting of the coordinate axis, the overall graphic is flattened to the point of being somewhat abstract.

But the six clearly protruding corners are still visible.

Chang Haonan grabbed the laser pen on the table, drew a few sharp lines on the screen, and looked at Han Chenfeng:
"Old Han, the design you proposed earlier was based on the theoretical prediction of the equilibrium resonance peak?"

"Yes, through the mirror symmetry of adjacent magnetic islands..."

The latter suddenly stopped talking halfway, his pupils shrinking slightly:

"and many more……"

He took the laser pointer and circled a few key points on the topology map:

"It seems that this is the opposite... When the magnetic surface rotation angle and the disturbance frequency form a rational number relationship, the even symmetric arrangement that should suppress the expansion of the random layer may lead to stronger resonance due to the position coherence of the normalized magnetic flux?"

"This should be."

Although Chang Haonan gave a positive answer, the expression on his face did not relax, and he was obviously still considering longer-term issues.

Han Chenfeng has already thought of a new solution:
"So, if we control the current phase of the upper and lower sets of active control coils at 180° and obtain an oddly symmetrical coil configuration, wouldn't it be possible to greatly reduce the degree of distortion of the magnetic field topology?"

Chang Haonan's temples were throbbing. He didn't answer immediately, but just replayed the video surveillance on his computer when the alarm went off.

The inner wall of the disk generator was glowing with a crystal-clear indigo fluorescence.

This is a sign of ionic liquid penetration into regions of weak magnetic confinement.

After thinking for a long time, Chang Haonan nodded and agreed to the plan proposed by the other party:

"At this stage... we can first make improvements according to what Lao Han said."

Han Chenfeng's face lit up with joy at first, but his expression quickly froze on his face.

Since we say “at this stage”, it means that there will be major changes later.

And Chang Haonan quickly explained:

"During the simulation phase, as long as the apparent topological structure of the magnetic field can be maintained stable, it will be fine. If it cannot be maintained stable, the machine can be shut down and restarted without delaying the acquisition of necessary operating parameters... However, if the problem of magnetic surface instability cannot be fundamentally solved and only the coil configuration is changed, it is equivalent to consuming precious ionization seeds in exchange for temporary stable operation."

"And we must also consider that a true closed-loop nuclear magnetohydrodynamic power generation system does not have a primary or secondary circuit. Even if we don't consider the cost, it is impossible to open the lid of the nuclear reactor and add ionized seeds. So this is unacceptable for practical applications..."

(End of this chapter)