Arc-vaporization is one of the common methods to synthesize single-walled carbon nanotubes (SWNTs). However the detailed synthesis mechanism is still not clear, and the synthesis of longer and chirality-selected SWNTs has not been obtained. Here influence of the gravity G = 1 g(0), 2 g(0). and 3 g(0) is studied in order to develop the synthesis method of SWNTs. Simultaneously, calculations of heat convection are also carried out by using a fluid simulation program and the results are compared with the experimental results. (C) 2009 Elsevier B.V. All rights reserved.