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Notation

One symbol table for the project, with the equivalents in the thesis, in Dullemond’s notes and coag_py, and the identifier planned for the Rust code. Units are SI (ADR 0003).

Indices

ProjectThesisDullemondRustMeaning
i, ji, ji, j (or i_l, j_l for samples)i, jColliding bins. With several properties, a flattened multi-index (ADR 0004).
kkkkReceiving bin.
k̄k̄k̄k_lowBin with m_k̄ ≤ m_i + m_j < m_k̄+1.
slsSample index, s = 1..S.
nm (time step, clashes with mass)stepTime step index.

Grids

ProjectThesisDullemond / coag_pyRustUnitMeaning
N_m𝒩_mN_m, nmn_massMass bins.
N_φ𝒩_pN_φn_fillFilling factor bins (M9).
m_km_k^cmgrain[k]mass.center(k)kgBin center (geometric mean on log grid).
m_{k±1/2}m_k^bmigrainmass.edge(k)kgBin edges.
Δm_kΔm_kdmgrainmass.width(k)kgBin width.
q_mmass.ratio()m_{k+1}/m_k; must be < 2 for cancellation handling (coag_py assert).
r, Δrr, 𝒩_rradiusmRadial grid.
t_n, Δtt, Δttime, dtt, dtsTime.

Disk and gas

SymbolThesis value / definitionUnit
M_, L_M_⊙, L_⊙kg, W
q_diskM_disk/M_* = 0.01
ε_dgM_dust/M_gas = 0.01
μ, m_g2.3, μ m_p, kg
φ_fflaring angle 0.05rad
T_mid(r)(φ_f/2 · L_*/(4π r² σ_SB))^{1/4}K
c_ssqrt(k_B T / m_g)m s⁻¹
Ω_Ksqrt(G M_*/r³)s⁻¹
H_pc_s/Ω_Km
Σ_g(r)Σ₀ r^{-σ}, σ = 0.8 (thesis), 1 (diskmodel.py)kg m⁻²
ρ_g^midΣ_g / (sqrt(2π) H_p)kg m⁻³
u_thsqrt(8/π) c_sm s⁻¹
λ_mfp1/(n_g σ_H₂), σ_H₂ = 2·10⁻¹⁹ m²m
ν_mol½ u_th λ_mfpm² s⁻¹
ν_tα c_s H_p, α = 10⁻³m² s⁻¹
Reα c_s H_p / ν_mol
u_g-3/(Σ_g sqrt r) ∂_r(Σ_g ν_t sqrt r) (must use ν_t, see thesis review F6)m s⁻¹
u_n-E_d ∂_r P_g / (2 ρ_g Ω_K), E_d = 1m s⁻¹
v_tsqrt(α) c_s (turbulent velocity of largest eddies)m s⁻¹

Dust

ProjectThesiscoag_pyUnitMeaning
ρ_sρ_s = 1600rhosolidkg m⁻³Material density.
a_ka_kmRadius, (3 m / (4π ρ_s φ))^{1/3}.
St_kSt_its*omkStokes number.
Δv_ijΔv_ijdvm s⁻¹Total relative velocity, RMS of components BR, RD, AZ, TU, (DS).
v_frag1m s⁻¹Fragmentation threshold.
v_bouncem s⁻¹Bouncing threshold (M3).

Rates, kernels, estimators

ProjectThesiscoag_py / notesUnitMeaning
C_ijR^coll_ijCij, C(m₁,m₂)m³ s⁻¹Collision rate coefficient σ_ij Δv_ij.
P^x_ijP^x_ijOutcome probability, x ∈ {coag, bounce, frag}.
R^x_ijR^x_ijm³ s⁻¹C_ij P^x_ij.
X_kijX_kijPer-collision change in N_k (recipe weights).
K_kijK_kijKkijm³ s⁻¹Σ_x R^x_ij X^x_kij (symmetrized in i, j).
F_k(N)∂N_k/∂tcompute_kernel_summ⁻³ s⁻¹Σ_ij K_kij N_i N_j.
J_klmatrix='J's⁻¹∂F_k/∂N_l.
p_ijP^sample_ijF_i F_jPair proposal probability.
π_ijInclusion probability (sampling without replacement).
Sρ_sample N_m²NranNumber of draws.
F̂_kEq. 1.70m⁻³ s⁻¹MC estimate of F_k.
ΔM^net_ijΔM^net_ijkg m³ s⁻¹Σ_k m_k |K_kij|, mass throughput of pair (i, j).

Diagnostics

SymbolDefinitionMeaning
δ_M(t)(Σ m_k N_k(t) − Σ m_k N_k(0)) / Σ m_k N_k(0)Global mass error (thesis Δ_stab, chapter 3 definition).
ΔX^relsqrt(Σ_ij (Σ_k m_k X_kij/(m_i+m_j))²)Kernel mass error.
e_acc(t)mass-weighted error vs reference, see verificationReplaces the thesis Δ_acc, which divides by zero where the reference bin is empty.
B_k, V_kE[F̂_k] − F_k, Var[F̂_k]Estimator bias and variance.
η1/(e² · cost)Work-normalized efficiency.