this trend. As scattering polarization is frequency dependent, it is very unlikely that self-scattering is a main element in the polarization seen in the nebula. It is important to note that the different polarization processes are not mutually exclusive. If, as we have argued above, the radiation flux (via radiation anisotropy alignment) and self-scattering are not principal factors operating in the nebula, magnetic fields are likely responsible for the dust alignment and the observed polarization.\
Hence using the ALMA data and bearing in mind the above caveats, it is therefore possible to proceed with the mapping of the “magnetic architecture” of OH 231.8+4.2. Moreover, combining our new findings with the CARMA and SMA data, we now have multi-scale information on the dust distribution, and by extension on the magnetic field geometry. Table \[tabcomp\] compiles the characteristics of each available dataset and Fig.\[area\] shows the extent of the thermal dust emission for the different arrays as well as the HST H$\alpha$ emission. It is therefore possible to pinpoint the distribution of the thermal dust emission with respect to the ionized emission. Viewed on the plane of the sky, the former is centred on the central star of the nebula and extends 