deletions | additions       diff --git a/Scattering times.tex b/Scattering times.tex  index b10ab82..7fdb430 100644  --- a/Scattering times.tex  +++ b/Scattering times.tex 
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\section{DM Limits from Multipath Scattering}  In all discussions of the achievable and required timing resolution for SKA1\_Mid and SKA1\_Low, we must consider physical limitations imposed by propagation effects in the ISM. While the use of coherent dedispersion will remove the frequency dispersion caused by the ISM down to the Nyquist limit, multi-path multipath  scattering ultimately places a physical limit on the minimum resolvable structure in a given pulsar's pulse profile (and therefore minimum possible timing resolution). Interstellar scattering occurs when photons emitted from a pulsar are bent into our line of sight due to inhomogeneities in the ISM. Making the assumption of a single inhomogeneity (a \textit{scattering screen}) that is half way between observer and pulsar, this results in photons arriving at the telescope from a \textit{scattering disk} of some angular width. Photons arriving from different radii of the scattering disk have traveled different distances between pulsar and telescope and as such will be shifted in phase w.r.t. to unscattered photons arriving from the centre of the disk. These phase shifts result in a characteristic intensity variation with time, $I(t)$, given by  \begin{equation} 
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