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<p>This is a reminder of today's C&G seminar by Axel <span style="font-family: Arial; font-size: 14.6667px; white-space: pre-wrap;">Brandenburg at 13:15 in FC61.</span></p>
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<p><span style="font-family: Arial; font-size: 14.6667px; white-space: pre-wrap;">See you all there!</span></p>
<p><span style="font-family: Arial; font-size: 14.6667px; white-space: pre-wrap;">Jens, Raghu, Justin, Steffen</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Okc-wp1-at-fysik.su.se <okc-wp1-at-fysik.su.se-bounces@lists.su.se> on behalf of Raghunath Ghara <raghunath.ghara@astro.su.se><br>
<b>Sent:</b> Friday, February 22, 2019 12:08 PM<br>
<b>To:</b> okc-wp1-at-fysik.su.se@lists.su.se<br>
<b>Cc:</b> brandenb@nordita.org; Alsing Justin; Steffen Hagstotz<br>
<b>Subject:</b> [OKC-CosmologyGravity] C&G meeting - Feb 27 @ 13:15 in FC61 - talk by Axel Brandenburg</font>
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<p><span id="docs-internal-guid-fcaed554-7fff-44ab-7ce3-829b9807ce12"></span></p>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Dear All,</span></p>
<br>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">We will meet again for our next C&G seminar on 27th February
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">at 13:15 in room number FC61, department of Astronomy.
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">Axel Brandenburg from Nordita will give a seminar on the following
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">topic:</span></p>
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<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Title: Numerical simulations of gravitational waves from early
universe turbulence</span></p>
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<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Abstract:
</span></p>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Using direct numerical simulations of early universe hydromagnetic
turbulence with energy densities of up to 10% of the radiation energy </span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">density, we show that gravitational waves (GWs) with energy</span></p>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">densities
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">of about 10^{-10} times the critical energy density of the
</span><span style="background-color:transparent; font-size:11pt; font-family:Arial; vertical-align:baseline; white-space:pre-wrap">Friedmann
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">universe today were produced. Their characteristic strain today
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">is
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">found to be about 10^{-20} and should be observable with the
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">Laser
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">Interferometer Space Antenna (LISA) in the mHz range. The GWs
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">have positive (negative) circular polarization if the magnetic
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">field has
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">positive (negative) magnetic helicity. The GW energy reaches
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">a
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">constant value after the turbulent energy (kinetic or magnetic)
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">has
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">reached its maximum. Compressive modes are found to produce
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">about 10 times stronger GWs than solenoidal ones. After a fraction
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">of the Hubble time, a new shallow low frequency tail develops,
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">which
</span><span style="background-color:transparent; font-family:Arial; font-size:11pt; white-space:pre-wrap">is shown not to be an artifact of a finite domain size.</span></p>
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<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Date: February 27, Wednesday</span></p>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Time: 13:15</span></p>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Place: FC61</span></p>
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<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Cheers,</span></p>
<p dir="ltr" style="line-height:1.38; margin-top:0pt; margin-bottom:0pt"><span style="font-size:11pt; font-family:Arial; background-color:transparent; vertical-align:baseline; white-space:pre-wrap">Jens, Raghu, Justin & Steffen</span></p>
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