Table 2.
AO numerical simulation parameters.
| Numerical simulation configuration | |
|---|---|
| Telescope | D = 39 m diameter |
| ELT pupil model (no spider arms) | |
| von Kármán, ground layer only | |
| Turbulence | r0 at 500 nm: [8.9−21.5] cm |
| L0 = 25 m | |
| Speed: 10 m s−1 [10–40] | |
| On-axis natural guide star | |
| Guiding | Zero point: 2.6 × 1010 ph s−1 m−2 |
| Magnitude MR: [0–18] | |
| Tip-tilt mirror | |
| DMs | Hexagonal M4 model pattern |
| Pitch of 54 cm, coupling of 0.24 | |
| 4302 controlled actuators | |
| PWFS | |
| Subapertures | 92 × 92 – pixel size 42 cm. |
| 24 080 pixels used for control (a) | |
| Wavelength | Monochromatic, 658 nm |
| Throughput | 0.28 (including quantum efficiency) |
| Modulation | Circular, 4  radius |
| Readout noise | 0.3 e− |
| RTC controller | |
| Loop rate | fS = 500 Hz |
| Latency | τ = 2T = 4 ms (b) |
| Method | Two step modal linear integrator |
| Pixels →[mi]×[Gi]→ actuators | |
| Basis | DM Karhunen–Loève basis (c) |
| Real-time implementation | |
| CLOSE | p = 0.3; q± = 10−3; δkcrit = 5 |
| r = 0. [−0.5, 0.5]. | |
Notes. Values within brackets indicate probing ranges for various simulations reported across Sect. 5. Values preceding brackets indicate the default value for the parameter.
Bypassing the slope maps computation according to Guyon (2005), Clergeon (2014), and Deo et al. (2018b).
Extended to τ in [0, T, 2T] in Appendix C.
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