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UID:UW-Physics-Event-8186
DTSTART:20230206T180000Z
DURATION:PT1H0M0S
DTSTAMP:20240328T222950Z
LAST-MODIFIED:20230202T155833Z
LOCATION:2241 Chamberlin Hall
SUMMARY:The Eulerian space-time correlation of magnetohydrodynamic tur
bulence and the analysis of Parker Solar Probe measurements\, Plasma P
hysics (Physics/ECE/NE 922) Seminar\, Jean Carlos Perez\, Florida Inst
itute of Technology
DESCRIPTION:Understanding the Eulerian space-time correlation of magne
tohydrodynamic (MHD) turbulence\, as well as its possible universal pr
operties\, is of critical importance in the analysis and interpretatio
n of solar wind measurements when the Taylor hypothesis is not valid.
This so-called frozen-in-flow hypothesis posits that the temporal vari
ation of spacecraft signals is solely due to the spatial variation of
a frozen structure passing by the observation point\, in which case th
e turbulence dynamics can essentially be considered to be frozen in th
e plasma frame. The Parker Solar Probe (PSP) mission\, launched in 201
8\, is presently probing the near-Sun solar wind with an orbit that wi
ll reach its point of closest approach next year at a heliospheric rad
ius of approximately 0.045 au\, which is seven times closer than any p
revious mission. During each close encounter with the Sun\, the assump
tions supporting TH are expected to break down. In this talk\, I will
discuss a recent semi-phenomenological model of the Eulerian two-time
two-point (space-time) correlation for incompressible MHD turbulence
and its impact on the interpretation of PSP data. Using this model we
introduce a methodology that allows one to reconstruct the reduced ene
rgy spectrum of magnetic fluctuations vs spatial wavenumber from the f
requency spectrum of fluctuations measured by PSP near the Alfven crit
ical point\, where TH is expected to break down.
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URL:https://www.physics.wisc.edu/events/?id=8186
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