blackholesfactory 0.0.4

Black hole factory — create and simulate stellar, intermediate-mass, and supermassive black holes with full Kerr physics
Documentation 
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use crate::config::parameters::*;
use std::f64::consts::PI;

#[derive(Clone, Copy)]
pub enum DiskModel {
    ShakuraSunyaev,
    Adaf,
    Slim,
}

pub struct AccretionDisk {
    pub mass: f64,
    pub mdot: f64,
    pub spin: f64,
    pub inner_radius: f64,
    pub outer_radius: f64,
    pub alpha: f64,
    pub model: DiskModel,
}

impl AccretionDisk {
    pub fn new(mass: f64, mdot: f64) -> Self {
        let r_isco = isco_radius(mass, 0.0);
        Self {
            mass,
            mdot,
            spin: 0.0,
            inner_radius: r_isco,
            outer_radius: r_isco * 1e4,
            alpha: 0.1,
            model: DiskModel::ShakuraSunyaev,
        }
    }

    pub fn with_spin(mass: f64, mdot: f64, spin: f64) -> Self {
        let r_isco = isco_radius(mass, spin);
        Self {
            mass,
            mdot,
            spin,
            inner_radius: r_isco,
            outer_radius: r_isco * 1e4,
            alpha: 0.1,
            model: DiskModel::ShakuraSunyaev,
        }
    }

    pub fn with_model(mut self, model: DiskModel) -> Self {
        self.model = model;
        self
    }

    pub fn with_alpha(mut self, alpha: f64) -> Self {
        self.alpha = alpha.clamp(0.001, 1.0);
        self
    }

    pub fn with_outer_radius(mut self, r_out: f64) -> Self {
        self.outer_radius = r_out.max(self.inner_radius * 2.0);
        self
    }

    pub fn temperature_profile(&self, r: f64) -> f64 {
        if r < self.inner_radius {
            return 0.0;
        }
        let factor = 3.0 * G * self.mass * self.mdot / (8.0 * PI * SIGMA_SB * r.powi(3))
            * (1.0 - (self.inner_radius / r).sqrt());
        let base = factor.max(0.0).powf(0.25);
        match self.model {
            DiskModel::ShakuraSunyaev => base,
            DiskModel::Adaf => base * 0.3 * (r / self.inner_radius).powf(-0.5),
            DiskModel::Slim => {
                let edd_ratio = self.mdot * C * C * 0.1 / eddington_luminosity(self.mass);
                base * (1.0 + edd_ratio).ln().max(1.0).powf(0.25)
            }
        }
    }

    pub fn radial_profile(&self, n_points: usize) -> Vec<(f64, f64)> {
        let log_min = self.inner_radius.ln();
        let log_max = self.outer_radius.ln();
        (0..n_points)
            .map(|i| {
                let r =
                    (log_min + (log_max - log_min) * i as f64 / (n_points - 1).max(1) as f64).exp();
                (r, self.temperature_profile(r))
            })
            .collect()
    }

    pub fn luminosity(&self) -> f64 {
        let n = 500;
        let log_min = self.inner_radius.ln();
        let log_max = self.outer_radius.ln();
        let d_log = (log_max - log_min) / n as f64;
        (0..n)
            .map(|i| {
                let r = (log_min + (i as f64 + 0.5) * d_log).exp();
                let t = self.temperature_profile(r);
                2.0 * PI * r * SIGMA_SB * t.powi(4) * 2.0 * r * d_log
            })
            .sum()
    }

    pub fn radiative_efficiency(&self) -> f64 {
        let total = self.mdot * C * C;
        if total < 1e-30 {
            return 0.0;
        }
        (self.luminosity() / total).clamp(0.0, 0.42)
    }

    pub fn peak_temperature(&self) -> f64 {
        let r_peak = self.inner_radius * (49.0 / 36.0);
        self.temperature_profile(r_peak)
    }

    pub fn viscous_timescale(&self, r: f64) -> f64 {
        let h_over_r = 0.01;
        let omega = (G * self.mass / (r * r * r)).sqrt();
        1.0 / (self.alpha * h_over_r * h_over_r * omega)
    }

    pub fn total_mass(&self) -> f64 {
        let sigma_0 = self.mdot / (3.0 * PI * self.alpha * 0.01 * 0.01);
        let n = 200;
        let log_min = self.inner_radius.ln();
        let log_max = self.outer_radius.ln();
        let d_log = (log_max - log_min) / n as f64;
        (0..n)
            .map(|i| {
                let r = (log_min + (i as f64 + 0.5) * d_log).exp();
                let omega = (G * self.mass / (r * r * r)).sqrt();
                let sigma = sigma_0 / omega;
                2.0 * PI * r * sigma * r * d_log
            })
            .sum()
    }
}