I went back and forth (~5 mins each) with the BS M2 coil drivers between their nominal low noise state, and their higher noise higher range state.
When in the higher noise state (state 2), there seems to be consistently higher noise between about 55 Hz up to 100 Hz. In the attached plot the blue / green is the nominal low noise state, while red / pink is the high noise state.
I'll work on making this an actual noise projection that we can include in the noise budget, using Craig's code for quad PUM noise as a guide.
We were in the high noise state 2 from 20:56:45 - 21:04:00. Then in low noise state from 21:06:10 - 21:11:15 (there's a glitch during this time). Back to high noise from 21:13:20 - 21:19:40 (there's a small glitch during this time). Back to low noise from 21:21:50 - 21:28:00. All times UTC on 8 Nov 2023. After this I handed back to Robert.
I've finally had a look at projecting this noise to what it looks like in our nominal state.
I'm 'following along' the philosophy of Craig's quad coil driver noise projections in https://git.ligo.org/aligo_commissioning/labutils/-/blob/master/coil_drivers_state_switch/plot_all_quad_pum_switch.py
I take an average of the ASDs of the noisy time (blue trace), and an average of the nominal quiet time (orange trace), then subtract them to get the excess power (green trace). I then take the residual excess power, and divide by the ratio of filters that are different between the two times, and that gives the projection of this excess power to our nominal state (red trace).
The attached plot shows that the projected noise (red) is more than a factor of 100x below our nominal sensitivity (orange), so BS M2 coil driver noise should not be an (immediate) issue for us.
The notebook is in /ligo/home/jenne.driggers/LHO_work/2023_11_21_BS_coil_driver_noise_budget/BS_coil_driver_noise_projection.ipynb
