Magnetic Field Dropouts at Near-Sun Switchback Boundaries: A Superposed Epoch Analysis

Magnetic Field Dropouts at Near-Sun Switchback Boundaries: A Superposed Epoch Analysis. Farrell, W. M., MacDowall, R. J., Gruesbeck, J. R., Bale, S. D., & Kasper, J. C. Astrophysical Journal, Supplement Series, January, 1970.

Paper doi abstract bibtex

During Parker Solar Probe's first close encounter with the Sun in early 2018 November, a large number of impulsive rotations in the magnetic field were detected within 50 R $_{\textrm{s}}$; these also occurred in association with short-lived impulsive solar wind bursts in speed. These impulsive features are now called "switchback" events. We examined a set of these switchbacks where the boundary transition into and out of the switchback was abrupt, with fast B rotations and simultaneous solar wind speed changes occurring on timescales of less than ~10 s; these thus appear as step function-like changes in the radial component of B and V. Our objective was to search for any diamagnetic effects that might occur especially if the boundaries are associated with quick changes in density (i.e., a steep spatial density gradient at the switchback boundary). We identified 25 switchback entries where the radial component of B, B $_{\textrm{r}}$, quickly transitioned from large negative to positive values and V $_{\textrm{r}}$ simultaneously abruptly increased (i.e., step-up transitions) and 28 switchback exits where B $_{\textrm{r}}$ quickly transitioned from large positive to negative values and V $_{\textrm{r}}$ simultaneously abruptly decreased (i.e., step-down transitions). We then performed a superposed epoch analysis on each of these sets of events. We found these fast-transitioning events typically had a clear and distinct decrease in the magnetic field magnitude by 7%–8% detected exactly at the boundary. The presence of the dropout suggests there is a diamagnetic current present at the boundary.

@article{farrell_magnetic_1970,
	title = {Magnetic {Field} {Dropouts} at {Near}-{Sun} {Switchback} {Boundaries}: {A} {Superposed} {Epoch} {Analysis}},
	url = {http://iopscience.iop.org/0067-0049/249/2/28?utm_source=researcher_app&utm_medium=referral&utm_campaign=RESR_MRKT_Researcher_inbound},
	doi = {10.3847/1538-4365/ab9eba},
	abstract = {During Parker Solar Probe's first close encounter with the Sun in early 2018 November, a large number of impulsive rotations in the magnetic field were detected within 50 \textit{R} $_{\textrm{s}}$; these also occurred in association with short-lived impulsive solar wind bursts in speed. These impulsive features are now called "switchback" events. We examined a set of these switchbacks where the boundary transition into and out of the switchback was abrupt, with fast \textit{B} rotations and simultaneous solar wind speed changes occurring on timescales of less than {\textasciitilde}10 s; these thus appear as step function-like changes in the radial component of \textit{B} and \textit{V}. Our objective was to search for any diamagnetic effects that might occur especially if the boundaries are associated with quick changes in density (i.e., a steep spatial density gradient at the switchback boundary). We identified 25 switchback entries where the radial component of \textit{B}, \textit{B} $_{\textrm{r}}$, quickly transitioned from large negative to positive values and \textit{V} $_{\textrm{r}}$ simultaneously abruptly increased (i.e., step-up transitions) and 28 switchback exits where \textit{B} $_{\textrm{r}}$ quickly transitioned from large positive to negative values and \textit{V} $_{\textrm{r}}$ simultaneously abruptly decreased (i.e., step-down transitions). We then performed a superposed epoch analysis on each of these sets of events. We found these fast-transitioning events typically had a clear and distinct decrease in the magnetic field magnitude by 7\%–8\% detected exactly at the boundary. The presence of the  dropout suggests there is a diamagnetic current present at the boundary.},
	journal = {Astrophysical Journal, Supplement Series},
	author = {Farrell, W. M. and MacDowall, R. J. and Gruesbeck, J. R. and Bale, S. D. and Kasper, J. C.},
	month = jan,
	year = {1970},
	keywords = {Researcher App},
}

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