Frequency Transition From Weak to Strong Turbulence in the Solar Wind

During a specific time window while approaching the Sun, longitudinal speed of Parker Solar Probe matches that Sun’s rotation. The spacecraft therefore co-rotates with and as long it does so, is immersed in solar-wind plasma same flow tube. This unique feature Probe’s orbital configuration exploited this work for first time, to investigate spectral properties turbulence stream, from large small scales, very close Sun. Standard diagnostics power, compressibility, intermittency are applied magnetic field data acquired by during its seventh encounter results clearly show presence frequency transition (at about 5 × 10 –3 Hz frame) within inertial range, where spectrum steepens an Iroshnikov-Kraichnan-like 3/2 Kolmogorov-like 5/3 scaling, Alfvénic content decreases, whereas grows. observational evidence interpreted scales dominated fluctuations (and thus poorly intermittent turbulent) nonlinear interactions more turbulent). To author’s knowledge, such weak strong range has been observed, certainly deserves further investigation, both theoretical perspective.