First Observation of Lion Roar Emission in Saturn's Magnetosheath

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F18%3A00487612" target="_blank" >RIV/68378289:_____/18:00487612 - isvavai.cz</a>
Alternative codes found
RIV/00216208:11320/18:10389393
Result on the web
<a href="http://dx.doi.org/10.1002/2017GL075919" target="_blank" >http://dx.doi.org/10.1002/2017GL075919</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1002/2017GL075919" target="_blank" >10.1002/2017GL075919</a>

Result language
angličtina
Original language name
First Observation of Lion Roar Emission in Saturn's Magnetosheath
Original language description
We present an observation of intense emissions in Saturn's magnetosheath as detected by the Cassini spacecraft. The emissions are observed in the dawn sector (magnetic local time similar to 06:45) of the magnetosheath over a time period of 11 h before the spacecraft crossed the bow shock and entered the unshocked solar wind. They are found to be narrow-banded with a peak frequency of about 0.16 f(ce), where f(ce) is the local electron gyrofrequency. Using plane wave propagation analysis, we show that the waves are right hand circularly polarized in the spacecraft frame and propagate at small wave normal angles (<10 degrees) with respect to the ambient magnetic field. Electromagnetic waves with the same properties known as ´lion roars´ have been reported by numerous missions in the terrestrial magnetosheath. Here we show the first evidence such emission outside the terrestrial environment. Our observations suggest that lion roars are a solar-system-wide phenomenon and capable of existing in a broad range of parameter space. This also includes 1 order of magnitude difference in frequencies. We anticipate our result to provide new insight into such emissions in a new parameter regime characterized by a higher plasma beta (owing to the substantially higher Mach number bow shock) compared to Earth.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10305 - Fluids and plasma physics (including surface physics)

Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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