<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: tahoma,new york,times,serif; font-size: 12pt; color: #000000'>Reminder<BR>
<DIV style="FONT-STYLE: normal; FONT-FAMILY: Helvetica,Arial,sans-serif; COLOR: #000; FONT-SIZE: 12pt; FONT-WEIGHT: normal; TEXT-DECORATION: none">
<DIV style="FONT-FAMILY: tahoma,new york,times,serif; COLOR: #000000; FONT-SIZE: 12pt">
<DIV style="FONT-STYLE: normal; FONT-FAMILY: Helvetica,Arial,sans-serif; COLOR: #000; FONT-SIZE: 12pt; FONT-WEIGHT: normal; TEXT-DECORATION: none"><BR><BR>
<STYLE>p { margin: 0; }</STYLE>
<DIV style="FONT-FAMILY: tahoma,new york,times,serif; COLOR: #000000; FONT-SIZE: 12pt">ACCELERATOR SEMINAR<BR><BR>"Overview of Studies of <SPAN id=DWT9255 class=ZM-SPELLCHECK-MISSPELLED word="Microbunching">Microbunching</SPAN> Instability"<BR><BR><SPAN id=DWT9256 class=ZM-SPELLCHECK-MISSPELLED word="Rui">Rui</SPAN> Li<BR><SPAN id=DWT9257 class=ZM-SPELLCHECK-MISSPELLED word="CASA">CASA</SPAN> Group, Jefferson Lab<BR><BR>
<P class=MsoNormal><SPAN id=DWT9258 class=ZM-SPELLCHECK-MISSPELLED word="Microbunching">Microbunching</SPAN> instability is a physical process when the initial longitudinal density modulation in an electron bunch induces energy modulation through collective interaction, such as the longitudinal space charge or coherent synchrotron radiation (<SPAN id=DWT9259 class=ZM-SPELLCHECK-MISSPELLED word="CSR">CSR</SPAN>). This energy modulation is further converted to larger density modulation through momentum compaction of the lattice, causing amplification of the initial modulation. This process is often parasitic to the generation or transport of high brightness beams, and can compromise diagnostics by coherent optical transition radiation (<SPAN id=DWT9260 class=ZM-SPELLCHECK-MISSPELLED word="COTR">COTR</SPAN>) or degrade the <SPAN id=DWT9261 class=ZM-SPELLCHECK-MISSPELLED word="FEL">FEL</SPAN> performance in the downstream <SPAN id=DWT9262 class=ZM-SPELLCHECK-MISSPELLED word="undulator">undulator</SPAN>.<SPAN style="mso-spacerun: yes"> </SPAN>In this seminar, we’ll review the important works on the observation of <SPAN id=DWT9263 class=ZM-SPELLCHECK-MISSPELLED word="microbunching">microbunching</SPAN> instability, and the theory and simulation using impedance results based on 1D bunch model. We will then present recent progress in <SPAN id=DWT9264 class=ZM-SPELLCHECK-MISSPELLED word="microbunching">microbunching</SPAN> studies based on more refined models of longitudinal space charge and <SPAN id=DWT9265 class=ZM-SPELLCHECK-MISSPELLED word="CSR">CSR</SPAN>, and highlight the mitigation method and possible application of the instability in accelerator designs.</P><BR>Thursday, June 27, 2013<BR>11:00 a.m.<BR><SPAN id=DWT9266 class=ZM-SPELLCHECK-MISSPELLED word="CEBAF">CEBAF</SPAN> Center, Room F113<BR><BR></DIV><BR></DIV></DIV></DIV></div></body></html>