@article{Good:2021:10.5194/egusphere-egu21-14974,
author = {Good, S and Kilpua, E and Ala-Lahti, M and Osmane, A and Bale, S and Zhao, L},
doi = {10.5194/egusphere-egu21-14974},
title = {Cross helicity of magnetic clouds observed by Parker Solar Probe},
url = {http://dx.doi.org/10.5194/egusphere-egu21-14974},
year = {2021}
}

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TY  - JOUR
AB  - <jats:p>&lt;p&gt;Magnetic clouds are large-scale transient structures in the solar wind with low plasma &lt;em&gt;&amp;#946;&lt;/em&gt;, low-amplitude magnetic field fluctuations, and twisted field lines with both ends often connected to the Sun. We analyse the normalised cross helicity, &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt;, and residual energy, &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;r&lt;/sub&gt;, in magnetic clouds observed by Parker Solar Probe (PSP). In the November 2018 cloud observed at 0.25 au, a low value of &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt; was present in the cloud core, indicating that wave power parallel and anti-parallel to the mean field was approximately balanced, while the cloud&amp;#8217;s outer layers displayed larger amplitude Alfv&amp;#233;nic fluctuations with high &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt; values and &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;r&lt;/sub&gt; ~ 0. These properties are compared and contrasted to those found in clouds observed by PSP at larger heliocentric distances. We suggest that low &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt; is likely a common feature of magnetic clouds given their typically closed field structure, in contrast to the generally higher &lt;em&gt;&amp;#963;&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt; found on the open field lines of the solar wind.&lt;/p&
AU  - Good,S
AU  - Kilpua,E
AU  - Ala-Lahti,M
AU  - Osmane,A
AU  - Bale,S
AU  - Zhao,L
DO  - 10.5194/egusphere-egu21-14974
PY  - 2021///
TI  - Cross helicity of magnetic clouds observed by Parker Solar Probe
UR  - http://dx.doi.org/10.5194/egusphere-egu21-14974
ER  - 

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