Direct Multipoint Observations Capturing the Reformation of a Supercritical Fast Magnetosonic Shock. (arXiv:2104.01123v1 [physics.space-ph])
<a href="http://arxiv.org/find/physics/1/au:+Turner_D/0/1/0/all/0/1">D. L. Turner</a>, <a href="http://arxiv.org/find/physics/1/au:+Wilson_L/0/1/0/all/0/1">L. B. Wilson III</a>, <a href="http://arxiv.org/find/physics/1/au:+Goodrich_K/0/1/0/all/0/1">K. A. Goodrich</a>, <a href="http://arxiv.org/find/physics/1/au:+Madanian_H/0/1/0/all/0/1">H. Madanian</a>, <a href="http://arxiv.org/find/physics/1/au:+Schwartz_S/0/1/0/all/0/1">S. J. Schwartz</a>, <a href="http://arxiv.org/find/physics/1/au:+Liu_T/0/1/0/all/0/1">T. Z. Liu</a>, <a href="http://arxiv.org/find/physics/1/au:+Johlander_A/0/1/0/all/0/1">A. Johlander</a>, <a href="http://arxiv.org/find/physics/1/au:+Caprioli_D/0/1/0/all/0/1">D. Caprioli</a>, <a href="http://arxiv.org/find/physics/1/au:+Cohen_I/0/1/0/all/0/1">I. J. Cohen</a>, <a href="http://arxiv.org/find/physics/1/au:+Gershman_D/0/1/0/all/0/1">D. Gershman</a>, <a href="http://arxiv.org/find/physics/1/au:+Hietala_H/0/1/0/all/0/1">H. Hietala</a>, <a href="http://arxiv.org/find/physics/1/au:+Westlake_J/0/1/0/all/0/1">J. H. Westlake</a>, <a href="http://arxiv.org/find/physics/1/au:+Lavraud_B/0/1/0/all/0/1">B. Lavraud</a>, <a href="http://arxiv.org/find/physics/1/au:+Contel_O/0/1/0/all/0/1">O. Le Contel</a>, <a href="http://arxiv.org/find/physics/1/au:+Burch_J/0/1/0/all/0/1">J. L. Burch</a>
Using multipoint Magnetospheric Multiscale (MMS) observations in an unusual
string-of-pearls configuration, we examine in detail observations of the
reformation of a fast magnetosonic shock observed on the upstream edge of a
foreshock transient structure upstream of Earth’s bow shock. The four MMS
spacecraft were separated by several hundred km, comparable to suprathermal ion
gyro-radius scales or several ion inertial lengths. At least half of the shock
reformation cycle was observed, with a new shock ramp rising up out of the
“foot” region of the original shock ramp. Using the multipoint observations, we
convert the observed time-series data into distance along the shock normal in
the shock’s rest frame. That conversion allows for a unique study of the
relative spatial scales of the shock’s various features, including the shock’s
growth rate, and how they evolve during the reformation cycle. Analysis
indicates that: the growth rate increases during reformation, electron-scale
physics play an important role in the shock reformation, and energy conversion
processes also undergo the same cyclical periodicity as reformation. Strong,
thin electron-kinetic-scale current sheets and large-amplitude electrostatic
and electromagnetic waves are reported. Results highlight the critical
cross-scale coupling between electron-kinetic- and ion-kinetic-scale processes
and details of the nature of nonstationarity, shock-front reformation at
collisionless, fast magnetosonic shocks.
Using multipoint Magnetospheric Multiscale (MMS) observations in an unusual
string-of-pearls configuration, we examine in detail observations of the
reformation of a fast magnetosonic shock observed on the upstream edge of a
foreshock transient structure upstream of Earth’s bow shock. The four MMS
spacecraft were separated by several hundred km, comparable to suprathermal ion
gyro-radius scales or several ion inertial lengths. At least half of the shock
reformation cycle was observed, with a new shock ramp rising up out of the
“foot” region of the original shock ramp. Using the multipoint observations, we
convert the observed time-series data into distance along the shock normal in
the shock’s rest frame. That conversion allows for a unique study of the
relative spatial scales of the shock’s various features, including the shock’s
growth rate, and how they evolve during the reformation cycle. Analysis
indicates that: the growth rate increases during reformation, electron-scale
physics play an important role in the shock reformation, and energy conversion
processes also undergo the same cyclical periodicity as reformation. Strong,
thin electron-kinetic-scale current sheets and large-amplitude electrostatic
and electromagnetic waves are reported. Results highlight the critical
cross-scale coupling between electron-kinetic- and ion-kinetic-scale processes
and details of the nature of nonstationarity, shock-front reformation at
collisionless, fast magnetosonic shocks.
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