  Magnetic switchbacks are distinct magnetic structures characterized by their
abrupt reversal in the radial component of the magnetic field within the
pristine solar wind. Switchbacks are believed to lose magnetic energy with
heliocentric distance. To investigate this switchbacks originating from similar
solar source regions are identified during a radial alignment of the Parker
Solar Probe (PSP; 25.8 solar radii) and Solar Orbiter (SolO; 152 solar radii).
We found that 1) the dynamic and thermal pressures decrease at the switchback
boundaries by up to 20% at PSP and relatively unchanged at SolO and magnetic
pressure jump across the boundary remains negligible at both distances, and 2)
bundles of switchbacks are often observed in switchback patches near the Sun,
and in microstreams farther away. Background proton velocity (vp) is 10%
greater than the pristine solar wind (vsw) in microstreams, whereas vp ~ vsw in
switchback patches. Microstreams contain an average of 30% fewer switchbacks
than switchback patches. It is concluded that switchbacks likely relax
magnetically and equilibrate their plasma with the surrounding environment with
heliocentric distance. Switchback relaxation can, in turn, accelerate the
surrounding plasma. Therefore, it is hypothesized that magnetic relaxation of
switchbacks may cause switchback patches to evolve into microstreams with
heliocentric distance. Statistical analysis of PSP and SolO switchbacks is
underway to further test our hypothesis.
