A Novel Method for Estimating the Intrinsic Magnetic Field Spectrum of Kinetic-Range Turbulence

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10439902" target="_blank" >RIV/00216208:11320/21:10439902 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=oWY5R4eaWx" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=oWY5R4eaWx</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3390/atmos12121547" target="_blank" >10.3390/atmos12121547</a>

Result language

angličtina

Original language name

A Novel Method for Estimating the Intrinsic Magnetic Field Spectrum of Kinetic-Range Turbulence

Original language description

Understanding plasma turbulence below the ion characteristic scales is one of the key open problems of solar wind physics. The bulk of our knowledge about the nature of the kinetic-scale fluctuations comes from the high-cadence measurements of the magnetic field. The spacecraft frame frequencies of the sub-ion scale fluctuations are frequently around the Nyquist frequencies of the magnetic field sampling rate. Thus, the resulting &apos;measured&apos; time series may significantly differ from the &apos;true&apos; ones. It follows that second-order moments (e.g., power spectral density, PSD) of the signal may also be highly affected in both their amplitude and their slope. In this paper, we focus on the estimation of the PSD slope for finitely sampled data and we unambiguously define a so-called local slope in the framework of Continuous Wavelet Transform. Employing Monte Carlo simulations, we derive an empirical formula that assesses the statistical error of the local slope estimation. We illustrate the theoretical results by analyzing measurements of the magnetic field instrument (MFI) on board the Wind spacecraft. Our analysis shows that the trace power spectra of magnetic field measurements of MFI can be modeled as the sum of PSD of an uncorrelated noise and an intrinsic signal. We show that the local slope strongly depends on the signal-to-noise (S/N) ratio, stressing that noise can significantly affect the slope even for S/N around 10. Furthermore, we show that the local slopes below the frequency corresponding to proton inertial length, 5 &amp; GSIM;k lambda(pi)&gt; 1, depend on the level of the magnetic field fluctuations in the inertial range (P-in), exhibiting a gradual flattening from about -11/3 for high P-in toward about -8/3 for low P-in.

Czech name

—

Czech description

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Type

J_imp - 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

<a href="/en/project/GA19-18993S" target="_blank" >GA19-18993S: Transport of energy of solar wind variations from larger to smaller scales</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Atmosphere

ISSN

2073-4433

e-ISSN

—

Volume of the periodical

12

Issue of the periodical within the volume

12

Country of publishing house

CH - SWITZERLAND

Number of pages

21

Pages from-to

1547

UT code for WoS article

000743669900001

EID of the result in the Scopus database

2-s2.0-85116569679