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TYPICAL PROFILES AND DISTRIBUTIONS OF PLASMA AND MAGNETIC FIELD PARAMETERS IN MAGNETIC CLOUDS AT 1 AU Luciano Rodriguez[1], Jimmy J. Masias-Meza[2], Sergio.

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Presentation on theme: "TYPICAL PROFILES AND DISTRIBUTIONS OF PLASMA AND MAGNETIC FIELD PARAMETERS IN MAGNETIC CLOUDS AT 1 AU Luciano Rodriguez[1], Jimmy J. Masias-Meza[2], Sergio."— Presentation transcript:

1 TYPICAL PROFILES AND DISTRIBUTIONS OF PLASMA AND MAGNETIC FIELD PARAMETERS IN MAGNETIC CLOUDS AT 1 AU Luciano Rodriguez[1], Jimmy J. Masias-Meza[2], Sergio Dasso[2], Pascal Demoulin[3], Andrei Zhukov[1][4],  Adriana Gulisano[2][5], Marilena Mierla[1][6],Emilia Kilpua[7], Matthew West[1], Dana Lacatus[6],  Alin Razvan Paraschiv[6], Miho Janvier[8] [1]Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, [2]Universidad de Buenos Aires, [3]Observatoire de Paris, [4]Moscow State University, [5]Instituto Antártico Argentino, [6]Institute of Geodynamics of the Romanian Academy, [7]University of Helsinki, [8]Institut d'Astrophysique Spatiale ESWW13, November 2016, Ostende

2 Introduction: Magnetic Clouds
Zurbuchen and Richardson, 2006 Kataoka and Miyoshi, 2006

3 Introduction: method Superposed epoch analysis of 63 MCs at L1 ( ), in order to find the typical profiles in plasma and magnetic field parameters MC #1 MC #63 B 1 49 MC #1 MC #63 Avg. 0 Avg. 1 Avg. 49 MC Avg.

4 Profiles of 63 MCs at L1 B V T N β O+7/O+6 nα/np rmsBoB Time
Speed gradient Asymmetric peak B V Sheath region T N Minimum T Maximum O+7/O+6 Minimum β β O+7/O+6 Minimum rmsBob Maximum nα nα/np rmsBoB Rodriguez et al., 2016 (Solar Physics) Time

5 Desnsity peaks at the trailing edge of MCs
The peak in density is observed in 22 out of 63 MCs 3 most likely causes High speed stream compression Expansion Intrinsic processes at the Sun

6 Expansion B MCs are expanding structures. This expansión can create peaks in density. V N T β

7 Compression from a trailing HSS
B A HSS trailing the clouds is compressing them from the back creating peaks in density V N T β

8 Intrinsic processes at the Sun
B V For some events no expansión nor trailing HSS were detected, for them the density peak could have solar origin N T β

9 MC events with density peaks
High speed streams are the most likely cause, with 17 out of 22 events having them

10 Conclusions The peak in the magnetic field magnitude inside magnetic clouds is not symmetric, due to the MC expansion, a possible spatial asymmetry within the flux rope, and its interaction with the surrounding solar wind. The proton temperature, the magnetic field fluctuations and the plasma β are low throughout the duration of the MC. The expansion of the cloud is marked by the negative slope of the speed profile and the low proton temperature. The O+7/O+6 profile is clearly enhanced throughout the duration of the MC. The O+7/O+6 and the α-to-proton ratio present typical ICME values for a period extended well beyond the defined flux rope rear boundary. A log-normal distribution function can be used to describe the distribution of plasma and magnetic field parameters near the center of MCs. There are proton density peaks observed around the trailing edge of a significant fraction of the studied MCs (22 out of 63). The scenario with overtaking fast flows is sufficient to explain most of the observed proton density peaks.

11 Extra

12 Log-normal distributions


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