129: Chapter 129 The Challenges of Nuclear Fusion Engineering

He had long expected someone to come knocking, but he hadn't anticipated that the Chief Engineer of the nuclear fusion project would visit in person, and arrive so quickly.

He looked at Yang Shihai and said sincerely.

"Chief Engineer Yang, you are too polite.

Everything is for the development of our country's technology, so please feel free to speak your mind.

As long as it is within my capabilities, I will certainly do my best."

Yang Shihai nodded. The smile on his face faded, replaced by the solemnity characteristic of an engineering expert and a hint of imperceptible anxiety.

He leaned forward slightly and began to elaborate in a calm but clear tone.

"Professor Chen, to be honest, ever since we learned that you successfully proved the existence and smoothness of the Navier-Stokes Equation, our project team has been closely following your work.

The biggest challenge our tokamak device currently faces is focused on the stability of plasma confinement."

He paused, then began to slowly describe the various difficulties in the engineering.

"Turbulence inside the plasma. Existing magnetohydrodynamic models have significant deviations when predicting the energy and particle transport efficiency of turbulence under extreme conditions.

The actual energy loss we observe often far exceeds the model's calculated values."

Chen Youhua almost instinctively took up the conversation, tapping his fingertips on the sofa armrest while thinking.

"The essence of turbulence is the cascade and dissipation of nonlinear interactions.

The key to the proof of the Navier-Stokes Equation lies in handling the existence and smoothness under such extreme nonlinearity.

Your observation results strongly suggest that existing turbulence transport models have significant flaws in their constitutive relations or closure assumptions when describing high-parameter, multi-scale coupled plasma environments.

This requires a deeper mathematical framework to re-examine the generation, maintenance, and dissipation mechanisms of turbulence, especially its peculiarities under strong magnetic confinement."

Yang Shihai's eyes lit up; Chen Youhua's response, which went straight to the core, invigorated him.

"Exactly! When the model fails, it is equivalent to being blind in engineering.

Another tricky point is the Edge Localized Modes.

When the power is increased to a certain level, the plasma edge acts like a dam that has accumulated too much energy; it suddenly breaches, erupting with massive heat and particle flows that violently impact the first-wall materials.

We urgently need theoretical tools or control strategies that can predict or even actively suppress these eruptions."

Chen Youhua frowned slightly and thought.

"ELM... this is essentially a type of intense boundary instability eruption.

From a mathematical perspective, it may stem from the plasma pressure gradient, current distribution, and magnetic field configuration reaching a certain critical point, causing the topological structure of the confinement configuration to undergo a sudden change, resulting in an instantaneous release of energy.

To predict and control it, the key lies in accurately characterizing this critical state and finding methods to perturb the magnetic surface topology to release the pressure in advance or stabilize the boundary layer.

This requires more precise solutions and stability criteria for the nonlinear evolution equations of magnetohydrodynamic equilibrium and stability."

"Solutions and criteria..."

Yang Shihai repeated these two words and nodded with deep feeling.

"This is precisely the pain point of our theoretical group.

There is also the issue of high-energy particle confinement. The alpha particles produced by fusion have extremely high energy, and their behavior in a turbulent background and complex magnetic fields is like a wild horse off the leash. If they cannot be confined, not only is energy wasted, but they may also conversely destroy the overall stability of the plasma.

Our understanding of their transport mechanisms is still very vague."

Chen Youhua took up the conversation.

"The transport of high-energy particles in a turbulent magnetic field is essentially a complex stochastic dynamic process involving wave-particle interactions, resonance effects, and chaotic orbits.

Existing descriptions may overly simplify the statistical properties of the turbulent field and its coupling strength with particles.

Perhaps we need to develop new methods that combine kinetic descriptions with more precise turbulent field models, especially focusing on those key resonance regions and phase space structures that lead to rapid particle loss."

Yang Shihai took a deep breath and brought up the last, and most realistic, obstacle in engineering implementation.

"The refinement of theoretical models requires computation for validation and guidance.

But currently, for large-scale numerical simulations, to fully simulate the device scale, include all key physical processes, and achieve sufficiently high spatiotemporal resolution...

The consumption of computational resources is astronomical, and we cannot afford the time."

We urgently need more efficient and intelligent algorithms that can capture the key physics affecting the whole within an acceptable time."

Chen Youhua pondered for a moment.

"The computational bottleneck is a hard constraint.

Either innovation in algorithms, using the nonlinear iteration and fine-scale estimation ideas developed in the Navier-Stokes Equation proof, might allow us to design solvers better adapted to the strong nonlinear characteristics of plasma, reducing unnecessary computational overhead.

Or model order reduction—how to scientifically identify and retain dominant physical processes while discarding secondary details—which requires a deeper mathematical understanding of the system's intrinsic low-dimensional attractors or inertial manifolds."

Speaking of this, Chen Youhua paused, gave Academician Zheng a meaningful look, and continued.

"Artificial Intelligence may also provide new ideas in data assimilation and model optimization."

Academician Zheng understood and nodded at him.

Yang Shihai, having heard Chen Youhua's clear and pointed response, felt his anxiety lessen, replaced by the excitement of finding a kindred spirit and a deeper sense of expectation.

His tone was earnest and heavy.

"Professor Chen, we need your profound mathematical insight, we need the grasp of the essence of nonlinear problems that you demonstrated during the process of solving the Navier-Stokes Equation, to help us see through the fog and find the fulcrum to pry open these difficult problems.

Even if it is just some directional inspiration, it could be a huge breakthrough for us."

Every difficulty Yang Shihai described pointed to the most profound fields in fluid physics; its complexity and the stringent requirements for engineering implementation were far beyond what could be compared to ordinary academic problems.

He could feel the heavy sense of responsibility and urgency in the other person's words.

After Yang Shihai finished speaking, Chen Youhua was silent for a moment, then nodded.

He made no grand statements, but responded with the pragmatic attitude characteristic of a scientific researcher.

"Chief Engineer Yang, I understand the challenges you are facing.

Nuclear fusion is a major event concerning the country's destiny and the future of humanity. It is my honor to have the opportunity to contribute a small amount of effort. However,"

He added candidly.

"The physical environment of nuclear fusion plasma is extremely complex, involving physical processes far beyond fluid mechanics, including electromagnetism, atomic physics, materials science, and so on.

I cannot guarantee that I can provide a solution immediately, but I will try my best from a mathematical and theoretical perspective to see if I can provide some new ideas or analytical tools for the turbulence transport, boundary instability modeling, or numerical algorithm optimization you mentioned."

"That is enough!"

Yang Shihai's eyes lit up, and a look of relief appeared on his face.

"Professor Chen, your willingness to participate is the greatest support for us!

We are not asking for immediate answers; we only hope to use your wisdom to illuminate a corner of the path ahead.

We will communicate the specific cooperation methods, data sharing, confidentiality agreements, and so on in detail later. We will definitely not take up too much of your time; everything will be based on your research pace."

Academician Zheng watched from the side and nodded with gratification.

"Youhua, Chief Engineer Yang's side represents the country's vital equipment, and you represent the country's pillars.

Being able to facilitate such a cooperation makes this trip worthwhile for an old man like me."