Re: [ibsimu-forum] Too small step size exception
Status: Beta
Brought to you by:
tvkalvas
|
From: Kalvas, T. <tan...@jy...> - 2019-04-16 18:18:31
|
Dear Ornella, This looks ok. Please note that you do not define a beam with 880 uA, but you define a plasma flux which corresponds to 880 uA for a r=3 mm aperture. This would be exactly a beam with 880 uA current if there was no focusing effects before the collimating plasma electrode. But as you are calculating a plasma extraction system the plasma meniscus is formed and there are electric fields in the plasma sheath which affect the current being extracted. If you have a convex shape in the plasma meniscus there will be a focusing force at the sheath region, which increases the extracted current. This is what is happening here. Taneli -- Taneli Kalvas Ph.D., Senior researcher Department of Physics, room FL114 P.O. Box 35 (YFL) 40014 University of Jyväskylä, Finland Mobile: +358-44-314-1602 Fax: +358-14-617-411 Email: tan...@jy... ________________________________________ From: Ornella Leonardi <orn...@ln...> Sent: Tuesday, April 16, 2019 7:21:05 PM To: ibs...@li... Subject: [ibsimu-forum] Too small step size exception Dear all, I’m working with IBSimu from some weeks. I’m running a simulation on a positive Ion Source. I have a Mode_CYL geometry where I add a pexp_plasma at -3mm from the plasma electrode. The simulation converges and complete all iterations, but on the console I see bad value concerning total beam current. I add a beam of 880 micro Amp and during the iterations I get a total current on boundary 2 greater than the initial one. At Major cycle 0 I can read "Total beam current 0.00679A" I report the total current (@boundary 2) trend vs. # interaction: 0) 0.000946 A 1) 0.000974 A 2) 0.000969A 3) 0.000975 A 4) 0.001176 A 5) 0.000961A 6) 0.001096 A 7) 0.00103 A 8) 0.001031 A 9) 0.001027 A 10)0.001035A What am I doing wrong? I attached my source code to allow you to check if I made any mistakes. Thanks in advance. Regards. Ornella -- Ornella Leonardi, Ph.D Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Sud Via S. Sofia 62 95123 Catania (Italy) office: +39 095 542642 e-mail: orn...@ln...<mailto:orn...@ln...> |