From apjetv@mcmaster.ca Tue Nov 13 22:29:15 2007 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on fclx01.albanova.se X-Spam-Level: X-Spam-Status: No, score=0.6 required=7.0 tests=NO_REAL_NAME autolearn=no version=3.1.8 X-Original-To: brandenb@albanova.se Delivered-To: brandenb@albanova.se Received: from localhost (localhost [127.0.0.1]) by fclx01.albanova.se (Postfix) with ESMTP id D3C12B3549 for ; Tue, 13 Nov 2007 22:29:13 +0100 (CET) X-Virus-Scanned: amavisd-new at albanova.se Received: from fclx01.albanova.se ([127.0.0.1]) by localhost (fclx01.albanova.se [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tCgPB+x+f6qz for ; Tue, 13 Nov 2007 22:29:11 +0100 (CET) Received: from mss.uchicago.edu (mss.uchicago.edu [128.135.181.18]) by fclx01.albanova.se (Postfix) with ESMTP id 5F140B354E for ; Tue, 13 Nov 2007 22:27:58 +0100 (CET) Received: ("??"@mss.uchicago.edu) by mss.uchicago.edu id ; Tue, 13 Nov 2007 15:27:55 -0600 To: brandenb@nordita.dk Subject: Your ApJ Submission MS# 73352 Cc: ApJ-MS73352@mss.uchicago.edu From: apjetv@mcmaster.ca Reply-To: apjetv@mcmaster.ca, ApJ-MS73352@mss.uchicago.edu, apjetv@mcmaster.ca Message-Id: <20071113212755Z3509-370+18897@mss.uchicago.edu> Date: Tue, 13 Nov 2007 15:27:55 -0600 Status: RO Content-Length: 2762 Lines: 54 Dear Axel, Enclosed please find the referee's report on your submission to the ApJ entitled Magnetic Diffusivity Tensor and Dynamo Effects in Rotating and Shearing Turbulence by A. Brandenburg, K. -H. Raedler, M. Rheinhardt, and P. J. Kaepylae. When you resubmit the manuscript through the ApJ ftp site, please include a detailed cover letter containing the (mandatory) listing of the changes you've made to the text and your responses to the report. I have nothing of my own to add at this time. The Astrophysical Journal has adopted a policy that manuscript files become inactive, and are considered to have been withdrawn, a year after the most recent referee's report goes to the authors, provided a revised version has not been received since then. If you have any questions, feel free to contact me. Regards, Ethan T. Vishniac, Editor-in-Chief The Astrophysical Journal apjetv@mcmaster.ca ************************************** REFEREE'S REPORT I have now gone through the paper "Magnetic diffusivity tensor and dynamo effects in rotating and shearing turbulence" by A. Brandenburg et al. The paper uses a novel technique to determine the turbulent co-efficients related to mean magnetic field transport, in the presence of shear or rotation. The authors then use their results to examine what can explain large-scale magnetic field generation found in simulations of driven (non-helical) turbulence in the presence of shear. On the whole I find the paper to be quite interesting and having several important results on large-scale dynamo action, and so acceptable for publication in ApJ. I have a few minor comments for the authors below. Typo: section 2.4, magnetic and not magnetc Section 3.1: It may be better to add a line as to what Radler 1969 and Radler and Stepanov 2006 found, and then compare with their result. From the present text it is not clear in what way the simulation results are "consistent" with the above papers. Section 3.2; second paragraph, The last line "If confirmed, the critical value.." is ununderstandable to me as it stands. Figure 11 caption: The last line of the caption should read I think "The slope D_etaS/Dalpha S = 1/2 (corresponding to k_1/k_f = 1/5) is indicated by a dashed line" The authors say the Yousef et al results can not be due to the shear-current effect. Would they like to speculate if this is also due to the incoherent alpha-Omega effect? A minor complaint: Rotation is discussed in the paper in section 3.1 and then is not at all crucial in the rest of the paper. A line in the conclusion as to why the authors thought it important to include rotation would be useful for the reader. Appendix B: some more comments on how these stochastic equations are solved would aid the reader.