극초음속 플라스마 스텔스(Plasma Stealth) RF 감쇠 & 1,000Hz 0-Alloc C# 전자 충돌 진동수 서보 엔진

using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace ZeliDesk.Stem.PlasmaStealth
{
    /// <summary>
    /// 대기 환경 및 적 레이더 위협 신호 계측 구조체
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Pack = 8)]
    public readonly struct ThreatRadarEnvironment
    {
        public readonly double RadarFrequencyGHz; // 8.0 ~ 12.0 GHz (X-band)
        public readonly double AltitudeKm;        // 비행 고도 (km)
        public readonly double FlightMach;        // 비행 마하수
        public readonly double AmbientPressurePa; // 주변 대기압 (Pa)

        public ThreatRadarEnvironment(double fGhz, double altKm, double mach, double pressPa)
        {
            RadarFrequencyGHz = fGhz;
            AltitudeKm = altKm;
            FlightMach = mach;
            AmbientPressurePa = pressPa;
        }
    }

    /// <summary>
    /// 플라스마 발생기 고전압 방전 제어 명령
    /// </summary>
    public ref struct PlasmaDischargeCommand
    {
        public double DischargeVoltageKv; // 방전 전압 (kV)
        public double DischargeCurrentAmps;
        public double TargetElectronDensityM3;
        public double ExpectedAttenuationDb;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public PlasmaDischargeCommand(double vKv, double iAmp, double ne, double db)
        {
            DischargeVoltageKv = vKv;
            DischargeCurrentAmps = iAmp;
            TargetElectronDensityM3 = ne;
            ExpectedAttenuationDb = db;
        }
    }

    /// <summary>
    /// 1,000Hz 무할당 플라스마 스텔스 감쇠 제어 엔진
    /// </summary>
    public ref struct PlasmaStealthServoEngine
    {
        private const double ElectronMassKg = 9.1093837e-31;
        private const double ElementaryChargeC = 1.60217663e-19;
        private const double Epsilon0 = 8.8541878e-12;
        private const double LightSpeedM_S = 299792458.0;
        private const double PlasmaThicknessM = 0.05; // 5cm 플라스마 시스

        private double _filteredTargetNe;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void ExecuteControlCycle(
            in ThreatRadarEnvironment env,
            out PlasmaDischargeCommand command)
        {
            double omega = 2.0 * Math.PI * env.RadarFrequencyGHz * 1.0e9;

            // 1. 대기압 및 온도에 따른 전자-중성입자 충돌 진동수 nu_en 추정
            // nu_en ~ 5.3e9 * (P / 101325) * (300 / T)^0.5
            double nuEn = 5.3e9 * (env.AmbientPressurePa / 101325.0);
            nuEn = Math.Clamp(nuEn, 1.0e8, 5.0e10);

            // 2. 무반사 최대 흡수 조건의 최적 플라스마 진동수 산출 (omega_p^2 ~ omega^2 + nu_en^2)
            double targetOmegaPSq = Math.Pow(omega, 2.0) + Math.Pow(nuEn, 2.0);
            double optimalNe = (targetOmegaPSq * Epsilon0 * ElectronMassKg) / Math.Pow(ElementaryChargeC, 2.0);

            _filteredTargetNe = 0.85 * _filteredTargetNe + 0.15 * optimalNe;

            // 3. 복소 유전율 및 감쇠 계수 alpha 계산
            double epsReal = 1.0 - targetOmegaPSq / (Math.Pow(omega, 2.0) + Math.Pow(nuEn, 2.0));
            double epsImag = (targetOmegaPSq * nuEn) / (omega * (Math.Pow(omega, 2.0) + Math.Pow(nuEn, 2.0)));
            double epsMag = Math.Sqrt(epsReal * epsReal + epsImag * epsImag);

            double kappa = Math.Sqrt(Math.Max(0.0, 0.5 * (epsMag - epsReal)));
            double alpha = (omega / LightSpeedM_S) * kappa;
            double attenuationDb = 8.686 * alpha * PlasmaThicknessM;
            attenuationDb = Math.Clamp(attenuationDb, 0.0, 35.0); // 최대 35dB RCS 감쇠

            // 4. 고전압 글로우 방전기 전력 명령 산출 (파센 법칙 기반 전압/전류 맵핑)
            double breakdownVoltKv = 1.5 + (env.AmbientPressurePa / 1000.0) * 0.045;
            double dischargeCurrentA = (_filteredTargetNe / 1.0e18) * 1.25;

            command = new PlasmaDischargeCommand(breakdownVoltKv, dischargeCurrentA, _filteredTargetNe, attenuationDb);
        }
    }
}