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1. PLATON Final Meeting First Announcement Plasma Astrophysics of Heating, Flares and Wind Final Meeting of the PLATON Research Training Network 24 June - 25 June 2004 Strasbourg, France http://astro.u-strasbg.fr/~baty/PLATON/ The objective of this meeting is to
summarize and discuss the results obtained by the PLATON Research
Training Network over the four years of its existence (August 2000 -
July 2004), and to provide an outlook on future work in the PLATON
research areas. Information about the PLATON Network can be found on
the PLATON web site http://www-solar.mcs.st-and.ac.uk/~thomas/platon/.
The meeting is open to researchers who are not members of the eight PLATON research teams, and we encourage the participation of researchers from outside the network. However, as the total number of participants is restricted to 60, preference will be given to PLATON team members, should this number be exceeded. The meeting will have four sessions, with one session for each of the three main themes of PLATON (`Coronal Heating', `Flares', and `Wind') plus a fourth session (`MHD and kinetic aspects for future research') in which possible future directions of research, and topics related to, but not directly within the three PLATON research areas will be discussed. Each session will consist of an invited review talk and contributed talks. The invited speakers are Alan Hood, St. Andrews (Coronal Heating), Bernhard Kliem, Postdam (Flares, to be confirmed), Fabien Casse, FOM `Rijnhuizen' (Wind) and Eckart Marsch, MPIAe Katlenburg-Lindau (MHD and kinetic aspects for future research). Online registration and further information about meeting can be found under http://astro.u-strasbg.fr/~baty/PLATON. The Organising Committee: J Heyvaerts, T Neukirch, E Priest, R Keppens, F Moreno Insertis, H Baty.
2. PLATON Personnel News A number of Young Researchers
have started and/or ended their PLATON contracts since the last PLATON
Newsletter.
* FOM `Rijnhuizen' : Richard Archibald has completed his spell as a Pre-Doc with the FOM team in January (see Science News for a brief account of the work done by Richard). The FOM team were very positively impressed by Richard and are very pleased to have had him at `Rijnhuizen'. Richard is now applying for PhD positions, and we wish him the best of luck for his future. * Centre for Plasma Astrophysics, K.U. Leuven : Two new Young Researchers have started to work at the Leuven team. Emmanuel Chane is a French Pre-Doc who is in Leuven for 8 months (since 1 December 2003). Emmanuel is presently doing numerical simulations of the evolution of different CME models in combination with different solar wind models. Emmanuel has a Masters of Physics from the University of Lille, France, and after his graduation (2002) he has carried some postgraduate work at Strasbourg, France, and Cracow, Poland. Inigo Arregui is a Spanish Post-Doc, who did his PhD at the University of the Balearic Islands in Palma de Mallorca. Inigo is working on coronal loop oscillations. His PLATON contract has started on 1 January 2004 for 6 months, but he intends to stay in Leuven for a full year. A warm welcome to both of them ! * IAC The two IAC Post-Doctoral Young Researchers, Eoghan O'Shea and Vasilis Archontis have both finished their contracts. Eoghan's two year spell at the IAC came to an end at the beginning of January 2004, and Vasilis terminated his contract prematurely on 31 December 2003 to take up another postdoctoral position at the IAC that allows him to stay in La Laguna beyond the end of PLATON in July. We wish both Eoghan and Vasilis all the best for their future. The IAC team hope that they will be able to make a new appointment by the end of February to fill their remaining open person-months. * Ruhr-Universität Bochum The Bochum team welcome back Timo Laitinen from Turku, Finland, who already was a PLATON Pre-Doc in Bochum in 2001. He is now back for 5 months (1 January 2004 - 31 May 2004) as a Post-Doc. Welcome back, Timo ! * AIP Cristina Gabellieri has finished her spell as a PLATON pre-doc at the AIP on 31 December 2003 and has returned to Italy to start a PhD. We wish her all the best for her future.
3. PLATON Science News i) PLATON Activities at FOM 'Rijnhuizen'(by F. Casse, FOM) PLATON Pre-Doc Richard Archibald has worked on numerical simulations of jet launching from accretion disks with both VAC and the adaptive mesh refinement version of VAC (AMRVAC). During his time at FOM `Rijnhuizen', he has been able to reproduce existing simulations but also to investigate new accretion disk configurations, especially weakly and strongly magnetized ones. The work he has done using AMRVAC will enable us to achieve high resolution simulations of jet launching and jet propagation over large distances. A report on the results of Richard's work is available on the PLATON publication webpage. The collaboration on jet stability between Strasbourg and `Rijnhuizen' is continuing. This work involves H. Baty (Strasbourg), R. Keppens (FOM) and P. Comte (Institute of Fluid Mechanics of Strasbourg) and is using AMRVAC MHD 2D simulations describing the large scale coalescence of unstable Kelvin-Helmholtz modes which become less disruptive for the jet structure. (see Baty, Keppens and Comte, Phys. Plasmas 10, 4661 (2003)). In a collaboration between FOM and Leuven an important contribution to the understanding of the stability of transonic axisymmetric plasmas like accretion disks or tokamaks has been made. In their paper, the authors present a complete spectral description of a new type of local MHD instabilities called "trans-slow Alfvenic continuum modes". (see Goedbloed, Belien, van der Holst and Keppens, Phys. Plasmas 11, 28 (2004)). The work presented by F. Casse (FOM) (in collaboration with R. Keppens) at the St Andrews meeting last September on full MHD description of accretion-ejection structures has now appeared in ApJ (Casse and Keppens, ApJ 601, 90 (2004)). This work displays the first-ever axisymmetric MHD simulations of accretion disks launching jets including full energy equation and demonstrate without any doubt the ability of magnetic field to both extract energy from the accretion disk and focus the outflow into a cylindrical jet. Last but not least: Hans Goedbloed's and Stefaan Poedts' book has finally reached the editor stage (two volumes are expected). This book is compiling lectures covering an impressive range of the theory of magnetohydrodynamics both for beginners and experts. It should appear in 2004 and become part of every good library ! PRINCIPLES OF MAGNETOHYDRODYNAMICS With Applications to Laboratory and Astrophysical Plasmas by J.P. Goedbloed and S. Poedts (to appear with Cambridge University Press, 2004) ii) PLATON Activities at the IAC (by Fernando Moreno-Insertis) The flux emergence collaboration between the IAC team and the St. Andrews team has become a IAC-St Andrews-Copenhagen collaboration due to the now "official" move of Klaus Galsgaard from St. Andrews back to Copenhagen. The collaboration is making excellent progress and they have had a mini-meeting in Copenhagen in November and another mini-meeting in Tenerife in February. iii) PLATON Activities at the AIP (by Bernhard Kliem and Gherardo Valori) The initiation of solar eruptions (flares, eruptive filaments/prominences and CMEs) is being studied by Tibor Toeroek (PLATON pre-doc in St Andrews), Slava Titov (Bochum) and Bernhard Kliem (Potsdam). Using the approximate force-free loop equilibrium by Titov & Demoulin (1999), the first investigation of the kink instability in an arched line-tied loop was performed. The critical twist for onset of the m=1 kink mode is of the same magnitude, and a helical current sheet forms in a similar manner, as in the cylindrically symmetric case. This supports the long-standing suggestion that the kink instability can initiate impulsive, compact (non-eruptive) flares. In fact, the rise of the kink-unstable loop is halted by the action of the strong overlying field in the equilibrium, much in the same way as a filament in a "failed eruption" recently observed by Ji et al. (2003). However, an upward kinking arched loop forms a second, vertical current sheet by a pinching of the hyperbolic flux tube underneath. Such a current sheet is the main element of the "standard model" for the main phase of eruptive flares. The field lines that pass through this current sheet take a shape that is characteristic of transient soft X-ray sigmoids, which often brighten at the onset of solar eruptions. Moreover, many eruptive filaments/prominences clearly develop helical distortions during their rise. It is therefore tempting to suppose that the kink instability initiates eruptive events as well. Current investigations in the ongoing collaboration are directed at this question. Gherardo Valori reports that after the St. Andrews meeting last September he has "polished" some details of the nonlinear force free field extrapolation code he is working on. To test the code properly Gherardo used a nonlinear (numerical) force free equilibrium from the simulations of Tibor Toeroek and Bernhard Kliem (A&A 406, 1043-1059 (2003)). The test was successful, and he is now working on a characterization of the extrapolation parameters for that test. In connection with this work Rony Keppens (FOM `Rijnhuizen') visited the AIP group on 2-3 February 2004. |