Recent observations, particularly those obtained by the Gaia mission, have greatly enhanced our understanding of the three-dimensional (3D) structure and evolution of the interstellar medium (ISM). The ISM evolution cannot be fully understood without observing interstellar magnetic fields. Magnetic fields influence the galaxy evolution and the formation of clouds and stars. However, their role is poorly understood, mainly due to significant limitations in observing 3D magnetic fields.
To map the 3D magnetic fields, Tahani et al. (2018) developed a novel technique, based on Faraday rotation measurements, to detect the line-of-sight component of magnetic fields associated with molecular clouds. They examined the technique on the Orion A, Orion B, California, and Perseus molecular clouds and found that their results agreed well with the Zeeman measurements available in these regions. Tahani et al. (2019) incorporated these line-of-sight and Planck’s plane-of-sky magnetic field observations, along with models and statistical tools, to examine the 3D magnetic field morphology associated with the Orion A cloud. Finally, Tahani et al. (2022a,b) used Galactic magnetic field models to reconstruct the 3D magnetic field morphologies (including their directions) of the Orion A and Perseus clouds. These 3D studies provide novel constraints on theories for the formation and evolution of star-forming clouds. In this poster, I will discuss these 3D observing techniques and future directions.