Gas kinematics are an important part of the planet formation process .
Turbulence influences planetesimal growth and migration from the scale of sub-micron dust grains through gas-giant planets .
Radio observations of resolved molecular line emission can directly measure this non-thermal motion and , taking advantage of the layered chemical structure of disks , different molecular lines can be combined to map the turbulence throughout the vertical extent of a protoplanetary disk .
Here we present ALMA observations of three molecules ( DCO ^ { + } ( 3-2 ) , C ^ { 18 } O ( 2-1 ) and CO ( 2-1 ) ) from the disk around HD 163296 .
We are able to place stringent upper limits ( v _ { turb } < 0.06c _ { s } , < 0.05c _ { s } and < 0.04c _ { s } for CO ( 2-1 ) , C ^ { 18 } O ( 2-1 ) and DCO ^ { + } ( 3-2 ) respectively ) , corresponding to \alpha \lesssim 3 \times 10 ^ { -3 } , similar to our prior limit derived from CO ( 3-2 ) .
This indicates that there is little turbulence throughout the vertical extent of the disk , contrary to theoretical predictions based on the magneto-rotational instability and gravito-turbulence .
In modeling the DCO ^ { + } emission we also find that it is confined to three concentric rings at 65.7 \pm 0.9 au , 149.9 ^ { +0.5 } _ { -0.7 } au and 259 \pm 1 au , indicative of a complex chemical environment .