tritons 0.0.3

Triton celestial simulation crate for the MilkyWay SolarSystem workspace
Documentation 
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use sciforge::hub::prelude::constants::elements::atomic_mass;

pub struct ExosphereSpecies {
    pub name: &'static str,
    pub symbol: &'static str,
    pub molar_mass_kg_mol: f64,
    pub column_density_m2: f64,
    pub scale_height_m: f64,
}

pub struct CryovolcanicEndpoint {
    pub geyser_height_m: f64,
    pub n2_mass_rate_kg_s: f64,
    pub surface_pressure_pa: f64,
}

pub struct ExosphereEndpoint {
    pub body_radius_m: f64,
    pub species: Vec<ExosphereSpecies>,
}

fn n2_molar() -> f64 {
    2.0 * atomic_mass(7) * 1e-3
}
fn ch4_molar() -> f64 {
    (atomic_mass(6) + 4.0 * atomic_mass(1)) * 1e-3
}
fn co_molar() -> f64 {
    (atomic_mass(6) + atomic_mass(8)) * 1e-3
}
fn co2_molar() -> f64 {
    (atomic_mass(6) + 2.0 * atomic_mass(8)) * 1e-3
}

impl ExosphereEndpoint {
    pub fn triton() -> Self {
        Self {
            body_radius_m: crate::TRITON_RADIUS_M,
            species: vec![
                ExosphereSpecies {
                    name: "Dinitrogen",
                    symbol: "N2",
                    molar_mass_kg_mol: n2_molar(),
                    column_density_m2: 1e20,
                    scale_height_m: 50_000.0,
                },
                ExosphereSpecies {
                    name: "Methane",
                    symbol: "CH4",
                    molar_mass_kg_mol: ch4_molar(),
                    column_density_m2: 1e16,
                    scale_height_m: 20_000.0,
                },
                ExosphereSpecies {
                    name: "Carbon monoxide",
                    symbol: "CO",
                    molar_mass_kg_mol: co_molar(),
                    column_density_m2: 1e15,
                    scale_height_m: 30_000.0,
                },
                ExosphereSpecies {
                    name: "Carbon dioxide",
                    symbol: "CO2",
                    molar_mass_kg_mol: co2_molar(),
                    column_density_m2: 1e14,
                    scale_height_m: 15_000.0,
                },
            ],
        }
    }

    pub fn density_at_altitude(&self, species_symbol: &str, altitude_m: f64) -> f64 {
        self.species
            .iter()
            .find(|s| s.symbol == species_symbol)
            .map(|s| {
                let n_surface = s.column_density_m2 / s.scale_height_m;
                n_surface * (-altitude_m / s.scale_height_m).exp()
            })
            .unwrap_or(0.0)
    }

    pub fn total_column_density(&self) -> f64 {
        self.species.iter().map(|s| s.column_density_m2).sum()
    }
}

impl CryovolcanicEndpoint {
    pub fn triton_geyser() -> Self {
        Self {
            geyser_height_m: 8_000.0,
            n2_mass_rate_kg_s: 10.0,
            surface_pressure_pa: 1.4,
        }
    }

    pub fn plume_density_at_height(&self, height_m: f64) -> f64 {
        if height_m > self.geyser_height_m {
            return 0.0;
        }
        let frac = height_m / self.geyser_height_m;
        self.n2_mass_rate_kg_s * (1.0 - frac).powi(2)
    }
}