Angle of Attack

As mentioned, the Soyuz flies an AoA of -22.3 degrees. This allows it to use its aft (forward-facing because the capsule reenters retrograde) heat shield as an aerodynamic surface which provides lift.

This is know as a lifting reentry and is done to ensure the capsule descends more slowly; lengthening the deceleration time. This lowers the peak acceleration and spreads the thermal load over a longer time period. Without it, the Soyuz may experience peaks of ~20g acceleration - dangerous for both the crew and the capsule.

The Soyuz achieves its angle of attack by having a nearly symmetrical aerodynamic shape, but with an offset centre of mass. Due to the unpredictable nature of reentry, the amount of lift needs to be varied in order to target the landing site precisely. This is done by rolling the capsule which changes the alters the vertical component of the lift vector.

Ablative Shielding

The Soyuz descent module has an ablative heat shield that is used to dissipate the thermal energy of reentry by 'burning off'. This can be seen on the capsule in the form of soot.

Because of the capsule’s angle of attack, it is in fact the zenith (upward facing) side of the capsule which receives the most ablated material as it is raised slightly above the shelter of the heat shield and more into the airflow.

This effect can be seen in this image (Note: this is NOT the Soyuz descent module)