Great Country Academician

Chapter 838: Smooth Electromagnetic Research Work

The internal meeting of the aerospace field is still being held, and the discussion on the lunar orbital mass projector is going on hotly.

In the conference room, in addition to the questions and suggestions from experts and scholars in various fields on various details, the most common question is probably why the country suddenly started this "science fiction-level" project and who proposed this technology.

And unsurprisingly, a young figure emerged in everyone's mind, and a strong envy in their minds.

For everyone present, even the big guys at the academician level, there is no one who does not envy that person.

Before he was thirty years old, he had already stood at the pinnacle of the academic world.

The title of academician of the two academies, the double winner of the Fields Medal and the Nobel Prize, in terms of reputation, he has already stood at the top, which can be said to be the first person in history.

And in the field of scientific research, there is no need to say more.

Perhaps most people in the academic world envy him for holding several 100 billion projects, but those who know the inside story are more envious of the fact that all his research has always been discussed separately at the top.

It does not need to be reviewed by the Ministry of Science and Technology, nor does it need funds managed by the National Natural Science Foundation of China.

What others consider to be a super job is just a matter of moving his mouth and saying something to the higher-ups.

Just like the lunar orbital mass projector, a project that looks extremely sci-fi in the aerospace industry and costs hundreds of billions of dollars is just the result of a letter from one person.

Of course, most scholars and researchers are just envious.

Or, even if they are envious, they can't envy such things, and can only regard them as "myths" in their hearts.

After all, any of the technologies and achievements that Xu Chuan has completed would take a lifetime to study, or even fail to complete.

Just like controlled nuclear fusion technology.

Just five years ago, it was called "eternal fifty years" by the academic community. At that time, if anyone said that a controlled nuclear fusion reactor could illuminate the entire land of China in five years, I'm afraid everyone would think he must be crazy.

However, now, this story, which can be said to be a fantasy, has really happened on this red land.

Being able to do this, no matter which country he is in, I am afraid that things related to him will only be handled as special cases.

Just when the Space Agency was holding a seminar on the lunar orbital mass projector + lunar orbital space station, the initiator of this project locked himself in a villa at the foot of Zijin Mountain.

Gao Hongming acted quickly. After Xu Chuan asked for the experimental data of the electromagnetic railgun project, he got the complete experimental data from the military and research institutions and units with related experiments in just two days.

Sitting in the study, Xu Chuan held a bag of yogurt in his mouth and typed on the keyboard with both hands.

It is extremely difficult to establish a mathematical control model for the magnetic field inside the electromagnetic railgun.

Apart from other things, the analysis and calculation of three-dimensional elliptical electromagnetic fields and high-dimensional large-scale backscattering problems are world-renowned mathematical problems.

This problem has important scientific and industrial applications, including the determination of PDE coefficients, initial value reconstruction, estimation of field source functions, and verification of interface or boundary conditions, which require solving ill-posed nonlinear operator equations. It can be said that almost all of them come from its research.

What's more important is that it also involves the reflection, eddy current, diffusion and other effects of electromagnetic fields, which makes it even more complex.

It's no exaggeration to say that the complexity of this problem can be compared with some T1-level mathematical conjectures.

Of course, complexity is complexity, not difficulty, and there is still a region between the two.

Especially for Xu Chuan, it's not the first time to deal with such a high-complexity problem.

After all, he also solved the millennium problem that was as complicated as the NS equation.

He unravels the thread, finds the thread to solve the problem, and then cleans it up along the way, solving the problems in front of him one by one. This is what he did.

It sounds simple, but it is extremely difficult to find the most critical thread from a ball of thread that has been played with by a cat for countless days.

What's more, the problems that may be encountered in the process of unravelling the thread are not so easy to solve.

In the study room of the villa.

Xu Chuan is communicating with Xiao Ling, an AI academic assistant.

Like other mathematicians solving difficult problems, when faced with a highly complex problem, the first thing he did was to search, collect and read various related papers and literature.

However, compared to the previous time when he had to do it himself or ask student assistants to help him, which took a lot of time to collect these materials, now he can collect these materials much faster.

Just lock in a detailed range and classification, tell the AI ​​academic assistant Xiaoling the required paper direction and literature field, and it can get these done in a very short time.

Although the paper materials collected by Xiaoling still need Xu Chuan to go through them again, compared to the previous screening of a large number of papers by himself, this can greatly save his preliminary preparation work and time.

After spending two days going through the thesis materials collected by Xiao Ling, Xu Chuan sat at his desk and took out a stack of manuscript paper from the drawer and spread it flat on the mahogany desk.

His eyes fell on the tip of the pen he was holding. After thinking for a while, he wrote his first mathematical work on the manuscript paper.

[(+ k)u =0, in Dc, u = u^s + u^i, lim|x|→∞|x|^(n1)/2·(u^s/|x| iku^s ).]

This is the Helmholtz equation, and it is also one of the tools commonly used in mathematics to solve electromagnetic field scattering problems.

In layman's terms, if a problem involves the inverse problem of a partial differential equation (PDE).

Then this type of problem generally has the following form: given a PDE and some information about the equation solution u (based on practical application considerations, this information should be easier to obtain through measurement, such as boundary values ​​or asymptotic behavior at infinity, etc.

This is then used to invert some unknown information in the PDE, such as coefficients, domain, and even the model itself.

As for the backscattering problem, it is generally assumed that the wave cannot penetrate the scatterer, that is, the scattered wave field only exists outside the scatterer.

But obviously, this kind of 'limited' calculation method is not what Xu Chuan needs.

For electromagnetic railguns, various issues such as internal magnetic field reflection and derivation are much more complicated than this.

In the study, the soft light illuminated the manuscript paper. While thinking, Xu Chuan wrote on the paper and said to himself:

". Give appropriate boundary conditions on the boundary D of the scatterer. If the scatterer is acoustically soft, you can consider u|D = 0; and when the scatterer is sound-hard, we have

uν|D =0. "

"But on top of this, the so-called impedance boundary condition needs to be considered, that is, (u/v+λu)·|D = 0, λ∈ C, Imλ\u003e 0"

"Then the scattering field at infinite ν distance has the following asymptotic expression: u^s(x)= e^ik|x|/|x^(n1)/2{u∞(x)+ O(1/| x|)."

Looking at the manuscript paper under his pen, Xu Chuan's eyes showed a hint of joy.

According to his experience, before solving a complex problem, finding the entrance to the complex problem is the most effective and fastest way.

And as long as he found this opening, at least he would be able to see how to go next.

Regarding the magnetic field data problem of the electromagnetic railgun, he has successfully found the thread.

For Xu Chuan, it was only a year ago that he devoted himself wholeheartedly to theoretical research in mathematics.

After the weak Riemann Hypothesis was proved, he began to do more research in the fields of aerospace and physics.

However, for him, the familiar feeling of immersing himself in mathematical research work is not unfamiliar.

Especially in the fields he is interested in, every piece of additional knowledge acquired is like a dose of dopamine, bringing him satisfaction and happiness.

Especially when all his attention was focused on the black mathematical symbols on the white manuscript paper, it seemed as if the whole world had disappeared, leaving only the Arabic numerals and ancient Greek symbols in front of him.

The pen slides smoothly across the paper, leaving wonderful characters one after another, as if every stroke is a poem, and every word is a bright star, lighting up the whole world.

Late at night, a gentle lamp lights up in the quiet study, and the Purple Mountain outside the window seems to be sleeping. Occasionally, there are some rustling sounds, just like love words in a dream.

Staring at the manuscript paper on the desk, Xu Chuan's eyes were bright and he murmured softly:

".The first unique result can be obtained with the help of the spectral theory of the Laplacian operator: the far field generated by infinitely many plane waves can uniquely determine an acoustically soft scatterer."

"Using the singular source field method, we can solve the problem that the far field generated by infinite plane waves can uniquely determine an acoustic hard scatterer."

"Then if the incident wave is a time-harmonic electromagnetic wave, the corresponding PDE model is a time-harmonic Maxwell equation. That is"

"."

For Xu Chuan, he has to consider not only the analysis and calculation problems of mathematically solving the three-dimensional elliptical electromagnetic field and high-dimensional large-scale backscattering problems, but also the mathematical model part.

In the field of electromagnetic field application research, based on electromagnetic field theory and integrating new achievements in numerical calculation methods and computer software technology, a new branch of disciplines called electromagnetic field numerical calculation has been derived.

Numerical integration method is one of the basic contents in the application of numerical calculation methods. It not only lays the foundation for numerical quadrature of various types of integral expressions.

And with the increasing development of numerical calculation methods, it has become an indispensable component in the construction of various numerical methods.

However, for the analysis and calculation problems of three-dimensional elliptical electromagnetic fields and high-dimensional large-scale backscattering problems, due to the lack of compactness conditions caused by critical nonlinear terms, it is difficult to solve the problem through trapezoidal quadrature method, Simpson quadrature method, Gaussian quadrature method, etc. Product method and elliptic integral method are used to solve this problem.

But for Xu Chuan, it is not too difficult to creatively complete a new method for the lack of compactness conditions caused by critical nonlinear terms.

The only thing that needs to be considered is to combine computer software technology with the numerical calculation of anisotropic electromagnetic fields, and use the characteristics of fast calculation speed and high accuracy of computers to improve the speed and accuracy of numerical calculation of anisotropic electromagnetic fields.

The numerical calculation of rectangular long straight current-carrying wires is realized by the direct integration method of field source discretization, and these numerical calculation methods are compared.

According to the running results of the analytical solution and numerical solution calculation program of the magnetic field of long straight current-carrying wires, it can be seen that the numerical solution is very close to the analytical solution and can meet the general requirements of electromagnetic field engineering.

Although this may not completely solve the problem, at least he can solve part of the problem!

Thinking of this, Xu Chuan pushed the already filled draft paper aside and wrote a line of formula on a white paper again.

[× E^s ikH^s = 0, × H^s + ikE^s = 0 ]

Looking at the mathematical formula on the manuscript paper, Xu Chuan's mouth gradually curled up a smile.

It seems that he will study this problem in seclusion for a few days.

After stretching and yawning, Xu Chuan picked up his phone from the table, sent a text message to Zheng Hai, told him that he needed to study the math problem, and stood up and walked towards the bathroom.

Although at the beginning, he did not think that he could find the answer to this problem in just a few days.

But unexpectedly, the analysis and calculation of the three-dimensional elliptical electromagnetic field and high-dimensional large-scale backscattering problems were quite smooth.

In just two days, he had successfully found the entry point for this problem, and even completed the preliminary simulation calculation work on various problems such as magnetic field reflection and derivation.

The process was so smooth that Xu Chuan himself could not believe it.

As for now.

He was going to take a shower and sleep!

After getting up tomorrow, he would start to solve this problem formally.