Theme 05 05.001 intrator tom 6/08/2009 13:32 Theme 05 might be useful to add an FRC accomplishment as -- creation of high density (5e22m-3), high pressure (20-30 bar) frc plasmas 05.002 intrator tom 6/08/2009 13:58 Theme 05 just to amplify on the question on (paraphrased) "why bother spreading out our resources on tangents to mainstream approaches?" Especially since themes 1-4 call out physics and engineering, vs theme 5 that calls out configurations. response could include ... we need some game changers, and there is a long list (eg disruptions, magnet cost, simple geometry, lithium, no center stack, engineering simplicity and modularity that follows from simply connected, eases super conducting magnet implementation… ) 05.003 Milroy Richard 6/08/2009 14:00 Theme 05 On page 3 there is a summary of the FRC with four bullets. It should contain a bullet acknowleging the field-reversed-theta-pinch. I suggest that a bullet should be added at the top which reads something like: "High density, high temperature FRCs have been routinely formed in field reversed theta-pinch devices, over may years. 05.004 Jarboe Tom 6/08/2009 14:06 Theme 05 First spheromak bullet should not have"inductive" in it. 05.005 Sovinec Carl 6/08/2009 14:37 Theme 05 In 5.1.2 (Highlights), the first bullet for the spheromak needs clarification. The parameters that are listed have not been achieved simultaneously. What is meant by "steady-state inductive helicity injection?" Also, the 500 eV temperature is not a steady-state result. 05.006 Hsu Scott 6/08/2009 14:41 Theme 05 The language is too technical. At this point, the theme summary will be useful only for ourselves and OFES program managers. Thus, the impact will be very limited. If we aspire to achieve the impact of the BES documents (i.e., growth in the program and excitement beyond our own community), then our documents must be easily understood by any college educated person. Another comment is that the BES process did a good job of identifying engineering outcomes/deliverables (i.e., closed fuel cycle for advanced nuclear fission energy) and then working backwards to the discovery science that is needed. I do not think these connections are necessarily clear in our case. In fact, discovery science has not been emphasized enough. Ideally, the documents need to be rewritten, perhaps with the help of a professional science writer. We will be squandering the opportunity to achieve maximum impact if we take shortcuts now. These comments apply to all 5 themes. 05.007 Hazeltine Richard 6/08/2009 16:01 Theme 05 The cube is a good idea, but I find the present form misleading. Putting all the non-stellarator dots on the floor ignores the wealth of experiments and extensive theory on symmetry breaking in tokamaks. A more accurate and instructive picture would show the tokamak dot far below the stellarator, but not quite on the floor. 05.008 Woodruff Simon 6/08/2009 16:33 Theme 05 Three comments: 1. We should strke a balance between presentation of theme 5 as 'game changing' and 'relevant'. While concept specific innovations may well solve outstanding issues in mainline concepts, the opportunity presented by renew is to make connections to the broad program. There are only few of us trying to make fusion work, and it will likely take all of us. 2. Context for renew was set by the FESAC TAP: some very insightful figures ilustrating eg iter era parameter goals for each concept can be found in the final report. 3. If we want to communicate with a wider audience, consider handing the draft we (scientists) produce to a non-scientist to edit. 05.009 Milroy Richard 6/08/2009 20:54 Theme 05 On page 39 there is an equation with n(Te+Ti) ~ Be2 /2… Here the 2 should be a superscript. On the same page there is a "1019", where the 19 should be superscript 05.010 Milroy Richard 6/08/2009 20:58 Theme 05 The first paragraph 5.2.4.3 on page 40, was changed from the last draft, and the last two sentences seem to have lost their meaning. I would suggest the following paragraph. (NOTE: I changed the word "colliding" to "merging".) FRC flux sustainment requires overcoming the ohmic losses associated with maintaining the diamagnetic toroidal currents. However, the cross-field resistivity η_perp is found to be anomalously high and needs to be decreased for sustainment at low power. Present experimental facilities are capable of studying some aspects of RMF and merging spheromaks, although the latter cannot presently study steady-state current drive. Unless the experiment used to study large-s is capable of current-drive and sustainment, a new experiment is needed to extend present work and fill this gap. 05.011 Jarboe Tom 6/09/2009 13:39 Theme 05 Table at the end. #5 CT should have a 3. CTs make large contributions in efficient steady state current drive and CT injection fueling. On top of page 44. replace "The spheromaks ohmicly heated to e,peak > 20% before a strong pressure-driven instability occurred." with "The spheromaks ohmicly heated to e,peak > 20% before a pressure-driven interchange occurred, demonstrating ohmic heating to the beta limit. 05.012 Cohen Sam 6/10/2009 10:46 Theme 05 Place more emphasis on advanced fuels in CTs, to overcome some of the major materials issues caused by D-T burning and tritium breeding.