[WIP] Adding new alternate neutrino cooling first draft

Microphysics/neutrinos/kipp.H

@@ -0,0 +1,103 @@
+// This routine calculates the neutrino cooling rates using the approximations from Kippenhahn et al. 1989
+// using autodiff
+
+#ifndef KIP_NEUT_H
+#define KIP_NEUT_H
+
+#define _USE_MATH_DEFINES
+
+#include<iostream>
+#include<AMReX_REAL.H>
+#include<fundamental_constants.H>
+#include<microphysics_autodiff.H>
+
+using namespace amrex::literals;
+
+template<typename number_t>
+AMREX_GPU_HOST_DEVICE AMREX_INLINE
+// pair annihilation
+number_t kip_pair(const number_t& rho, const number_t& T9, const number_t& abar, const number_t& zbar){
+    // eq. 18.81
+    if (T9 < 2.0e0_rt){
+        return (4.9e18_rt/rho) * amrex::Math::powi<3>(T9) * admath::exp(-11.86*T9);
+    }
+    else{
+        return (4.45e15_rt/rho) * amrex::Math::powi<9>(T9);
+    }
+}
+
+template<typename number_t>
+AMREX_GPU_HOST_DEVICE AMREX_INLINE
+// photoneutrinos
+number_t kip_phot(const number_t& rho, const number_t& T9, const number_t& abar, const number_t& zbar){
+    // eq. 18.82
+    number_t ep_1 = (1.103e13_rt/rho) * amrex::Math::powi<9>(T9) * admath::exp(-5.93e0_rt / T9);
+    number_t ep_2 = 0.976e8_rt * amrex::Math::powi<8>(T9) / (1.0e0_rt + 4.2e0_rt * T9);
+    number_t rho_bar = 6.446e-6_rt * rho / (T9 + 4.2e0_rt * amrex::Math::powi<2>(T9));
+    number_t mu_e = abar / zbar;
+
+    return ep_1 + ep_2 / (mu_e + rho_bar);
+}
+
+template<typename number_t>
+AMREX_GPU_HOST_DEVICE AMREX_INLINE
+// plasmaneutrinos
+number_t kip_plas(const number_t& rho, const number_t& T9, const number_t& abar, const number_t& zbar){
+    number_t n_e = rho / (C::m_u);
+    // assuming non-degeneracy
+    // 18.83
+    number_t w0 = admath::sqrt((4.0e0_rt * M_PI * amrex::Math::powi<2>(C::q_e) * n_e) / C::m_e);
+    number_t gamma = (C::hbar * w0) / (C::k_B * T9);
+    number_t lambda = (C::k_B * T9) / (C::m_e * amrex::Math::powi<2>(C::c_light));
+    // 18.85
+    if (gamma < 1) {
+        return (3.356e19_rt/rho) * amrex::Math::powi<6>(lambda) * (1.0e0_rt + 0.0158_rt * amrex::Math::powi<2>(gamma)) * amrex::Math::powi<3>(T9);
+    } else {
+        return (5.252e20_rt/rho) * admath::pow(lambda, 7.5e0_rt) * admath::pow(T9, 1.5e0_rt) * admath::exp(-gamma);
+    }
+}
+
+template<typename number_t>
+AMREX_GPU_HOST_DEVICE AMREX_INLINE
+// bremsstrahlung neutrinos
+number_t kip_brem(const number_t& rho, const number_t& T9, const number_t& abar, const number_t& zbar){
+    // eq. 18.86
+    number_t T8 = T9 * 10.0e0_rt;
+    return 0.76e0_rt * (amrex::Math::powi<2>(zbar)/abar) * amrex::Math::powi<6>(T8);
+}
+
+AMREX_GPU_HOST_DEVICE AMREX_INLINE
+void kipp(const amrex::Real& temp, const amrex::Real& rho, const amrex::Real& abar,
+    const amrex::Real& zbar, amrex::Real& snu, amrex::Real& dsnudt, amrex::Real& dsnudrho, amrex::Real& dsnudz, amrex::Real& dsnuda){
+
+    amrex::Real T9 = temp * 1.0e-9_rt;
+
+    using number_t = autodiff::dual_array<1,4>;
+
+    number_t rho_dual = rho;
+    number_t T9_dual = T9;
+    number_t abar_dual = abar;
+    number_t zbar_dual = zbar;
+
+    autodiff::seed_array(rho_dual, T9_dual, abar_dual, zbar_dual);
+
+    number_t kip_pair_dual = kip_pair(rho_dual, T9_dual, abar_dual, zbar_dual);
+    number_t kip_phot_dual = kip_phot(rho_dual, T9_dual, abar_dual, zbar_dual);
+    number_t kip_plas_dual = kip_plas(rho_dual, T9_dual, abar_dual, zbar_dual);
+    number_t kip_brem_dual = kip_brem(rho_dual, T9_dual, abar_dual, zbar_dual);
+
+    // sum of all neutrino cooling rates
+
+    number_t snu_dual = kip_pair_dual + kip_phot_dual + kip_plas_dual + kip_brem_dual;
+
+    // extract derivatives
+    auto derivatives = autodiff::derivative(snu_dual);
+    dsnudrho = derivatives(1);
+    dsnudt = derivatives(2);
+    dsnuda = derivatives(3);
+    dsnudz = derivatives(4);
+
+    // extract value
+    snu = autodiff::val(snu_dual);
+}
+#endif // KIP_NEUT_H