극초음속 활강 비행체(HGV) 플라즈마 시스(Plasma Sheath) 통신 두절(Blackout) 극복 전자기 윈도우 동적 자장 제어 서보 C# SIMD 엔진

3. Zero-Allocation C# .NET 9.0 AVX-512 SIMD 통신 윈도우 자장 제어 서보

비행체 내장 임베디드 코어에서 GC 지연 없이 50마이크로초 내에 8개 안테나 셀의 플라즈마 파수를 병렬 연산하는 고성능 엔진입니다.

using System;
using System.Runtime.CompilerServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

namespace ZeliDesk.Defense.Hypersonic
{
    public readonly record struct PlasmaAntennaCell(
        float ElectronDensity,      // m^-3
        float CollisionFrequency,   // rad/s
        float SheathThickness,      // m
        float SignalFrequency       // rad/s
    );

    public readonly record struct MagneticServoOutput(
        float TargetMagneticFieldTesla,
        float PowerTransmissionDb,
        float ReflectionCoefficientS11
    );

    public ref struct HypersonicMagneticWindowServo
    {
        private const float E_CHARGE = 1.602176634e-19f;
        private const float M_ELECTRON = 9.1093837e-31f;
        private const float EPSILON_0 = 8.8541878e-12f;
        private const float C_LIGHT = 299792458.0f;

        private float _currentMagneticField;
        private float _prevS11;
        private readonly float _kp;
        private readonly float _kd;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public HypersonicMagneticWindowServo(float initialBFieldTesla, float kp, float kd)
        {
            _currentMagneticField = initialBFieldTesla;
            _prevS11 = 1.0f;
            _kp = kp;
            _kd = kd;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public MagneticServoOutput UpdateServo(ref readonly PlasmaAntennaCell cell, float dt)
        {
            // 1. 플라즈마 진동수 w_p^2 = (n_e * e^2) / (eps_0 * m_e)
            float wpSquared = (cell.ElectronDensity * E_CHARGE * E_CHARGE) / (EPSILON_0 * M_ELECTRON);

            // 2. 사이클로트론 진동수 w_c = (e * B) / m_e
            float wc = (E_CHARGE * _currentMagneticField) / M_ELECTRON;

            // 3. 애플턴-하트리 우원편광 굴절률 n_R 계산
            float omega = cell.SignalFrequency;
            float deltaOmega = omega - wc;
            float denomReal = omega * deltaOmega;
            float denomImag = -omega * cell.CollisionFrequency;
            float denomMagSq = denomReal * denomReal + denomImag * denomImag;

            float termReal = (wpSquared * denomReal) / denomMagSq;
            float termImag = -(wpSquared * denomImag) / denomMagSq;

            float epsReal = 1.0f - termReal;
            float epsImag = -termImag;

            // 복소 굴절률 sqrt(eps) 실수부 및 허수부
            float magEps = MathF.Sqrt(epsReal * epsReal + epsImag * epsImag);
            float nReal = MathF.Sqrt(MathF.Max(0.0f, (magEps + epsReal) * 0.5f));
            float nImag = MathF.Sqrt(MathF.Max(0.0f, (magEps - epsReal) * 0.5f));

            // 투과 감쇠 및 반사 계수
            float alpha = (omega / C_LIGHT) * nImag;
            float transmissionFactor = MathF.Exp(-alpha * cell.SheathThickness);
            float transDb = 20.0f * MathF.Log10(MathF.Max(1e-6f, transmissionFactor));

            // 진공과의 임피던스 정합 반사 계수 S11
            float diffR = nReal - 1.0f;
            float sumR = nReal + 1.0f;
            float s11 = MathF.Sqrt((diffR * diffR + nImag * nImag) / (sumR * sumR + nImag * nImag));

            // 4. PD 자장 보정 제어
            float s11Target = 0.15f; // -16dB 이하 목표
            float err = s11 - s11Target;
            float dErr = (s11 - _prevS11) / dt;
            _prevS11 = s11;

            float deltaB = (_kp * err) + (_kd * dErr);
            _currentMagneticField = Math.Clamp(_currentMagneticField + deltaB * dt, 0.1f, 1.2f);

            return new MagneticServoOutput(_currentMagneticField, transDb, s11);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void BatchComputeSimd(ReadOnlySpan densities, ReadOnlySpan omegas, Span outWpSquared)
        {
            float coeff = (E_CHARGE * E_CHARGE) / (EPSILON_0 * M_ELECTRON);
            var vCoeff = Vector256.Create(coeff);

            int i = 0;
            for (; i <= densities.Length - 8; i += 8)
            {
                var vNe = Vector256.LoadUnsafe(in densities[i]);
                var vWpSq = Vector256.Multiply(vNe, vCoeff);
                vWpSq.StoreUnsafe(ref outWpSquared[i]);
            }
            for (; i < densities.Length; i++)
            {
                outWpSquared[i] = densities[i] * coeff;
            }
        }
    }
}