토카막 핵융합로 동결 D-T 펠릿 주입 NGS 승화 & 1,000Hz 0-Alloc C# 심층 플라즈마 연료 보급 제어 엔진

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.TokamakFueling
{
    /// <summary>
    /// 토카막 플라즈마 노심 및 펠릿 비행 상태 구조체
    /// </summary>
    public readonly ref struct PelletFlightState
    {
        public double MinorRadiusMeters { get; }    // 토카막 소반경 위치 r (m)
        public double ElectronDensityM3 { get; }    // 국소 전자 밀도 ne (m^-3)
        public double ElectronTemperatureEv { get; }// 국소 전자 온도 Te (eV)
        public double PelletVelocityMps { get; }    // 펠릿 입사 속도 v_p (m/s)
        public double CurrentPelletRadiusMm { get; }// 현재 펠릿 반경 r_p (mm)

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public PelletFlightState(double r, double ne, double te, double vp, double rp)
        {
            MinorRadiusMeters = r;
            ElectronDensityM3 = ne;
            ElectronTemperatureEv = te;
            PelletVelocityMps = vp;
            CurrentPelletRadiusMm = rp;
        }
    }

    /// <summary>
    /// 1,000Hz 0-Alloc C# 펠릿 NGS 삭마 및 노심 밀도 도달 예측 엔진
    /// </summary>
    public ref struct PelletAblationEngine
    {
        private const double HydrogenSolidDensity = 3.0e28; // molecules/m^3
        private const double CngsConstant = 1.72e14;        // NGS 경험 계수

        private double _accumulatedDepositedParticles;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public PelletAblationEngine(double initialDeposited)
        {
            _accumulatedDepositedParticles = initialDeposited;
        }

        /// <summary>
        /// 1,000Hz 실시간 루프 (dt = 0.001s) 펠릿 삭마율 및 노심 침투 깊이 계산
        /// </summary>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void ProcessStep(
            in PelletFlightState state,
            out double ablationRateAtomsPerSec,
            out double nextPelletRadiusMm,
            out double penetrationFraction,
            out bool isPelletFullyBurned)
        {
            const double dt = 0.001; // 1ms 타임스텝
            double rpMeters = state.CurrentPelletRadiusMm * 1e-3;

            if (rpMeters <= 1e-6)
            {
                ablationRateAtomsPerSec = 0.0;
                nextPelletRadiusMm = 0.0;
                penetrationFraction = 1.0;
                isPelletFullyBurned = true;
                return;
            }

            // 1. NGS 삭마율 dn/dt = C * ne^(1/3) * Te^1.64 * rp^(4/3) / M^(1/6) (D-T 기준 M=2.5)
            double neTerm = Math.Pow(Math.Max(1e18, state.ElectronDensityM3), 1.0 / 3.0);
            double teTerm = Math.Pow(Math.Max(10.0, state.ElectronTemperatureEv), 1.64);
            double rpTerm = Math.Pow(rpMeters, 4.0 / 3.0);
            const double massFactor = 1.165; // (2.5)^(1/6)

            ablationRateAtomsPerSec = (CngsConstant * neTerm * teTerm * rpTerm) / massFactor;

            // 2. 반경 후퇴율 dr_p/dt
            double drpDt = -ablationRateAtomsPerSec / (4.0 * Math.PI * HydrogenSolidDensity * (rpMeters * rpMeters));
            double nextRpMeters = rpMeters + (drpDt * dt);

            if (nextRpMeters < 0.0)
            {
                nextRpMeters = 0.0;
                isPelletFullyBurned = true;
            }
            else
            {
                isPelletFullyBurned = false;
            }

            nextPelletRadiusMm = nextRpMeters * 1e3;

            // 3. 토카막 노심(r=0) 접근 침투도 (0: 플라즈마 경계, 1: 중심 도달)
            const double tokamakMinorRadiusA = 0.50; // a = 0.50m (KSTAR 기준)
            penetrationFraction = Math.Clamp(1.0 - (state.MinorRadiusMeters / tokamakMinorRadiusA), 0.0, 1.0);

            _accumulatedDepositedParticles += ablationRateAtomsPerSec * dt;
        }
    }
}