图 1  (a) $\left\langle \beta \right\rangle = 0.5{\text{%}} $时旋转变换以及压强的径向分布; (b) $\left\langle \beta \right\rangle = 0.5{\text{%}} $、环向角$\phi = {0^ \circ }$时所对应的初始庞加莱图. 黑色点表示$p/{p_0} < 1{\text{%}} $的区域, 蓝色点表示$1{\text{%}} \leqslant $$ p/{p_0} \leqslant 10{\text{%}} $的区域, 红色点表示$p/{p_0} > 10{\text{%}} $的区域, 绿色线为真空室

Fig. 1.  (a) Comparison of the radial dependence of the rotational transform and pressure, $\iota /2\pi $ with $\left\langle \beta \right\rangle = 0.5{\text{%}} $, between the HINT and VMEC codes; (b) the Poincaré plots of initial magnetic surfaces with $\left\langle \beta \right\rangle = 0.5{\text{%}} $ at toroidal angle $\phi = {0^ \circ }$, where the black, blue and red colors mark the regions of $p/{p_0} < 1{\text{%}} $, $1{\text{%}} \leqslant p/{p_0} \leqslant 10{\text{%}} $, and $p/{p_0} > $$ 10{\text{%}} $, respectively. The green line denotes the boundary of the vacuum vessel.

图 2  (a)环向电流密度剖面、(b)电流大小分布, 红色线为高斯电流密度分布, 蓝色线为常数电流密度分布

Fig. 2.  Profiles of (a) toroidal current density, (b) toroidal current, where the blue line is constant current and the red line is the Gaussian current.

图 3  平均磁岛宽度$\left\langle W \right\rangle $随电流大小I₀变化关系图

Fig. 3.  Average width of magnetic islands $\left\langle W \right\rangle $ as a function of toroidal current (${I_0}$).

图 4  (a)—(c) $ {I}_{0}=2, \text{ }4, \text{ }6\text{ kA} $时庞加莱磁面; (d)—(f) 为$ {I}_{0}=-2, \text{ }-4, \text{ }-6\text{ kA} $时庞加莱磁面

Fig. 4.  (a)–(c) Poincaré plots of magnetic surfaces with $ {I}_{0}=2, \text{ }4, \text{ }6\text{ kA} $; (d)–(f) the Poincaré plots of magnetic surfaces with $ {I}_{0}=-2, \text{ }-4, \text{ }-6\text{ kA} $.

图 5  电流大小对旋转变换的影响

Fig. 5.  Rotational transforms with different constant current.

图 6  平均磁岛宽度以及m/n = 5/2有理面处磁剪切随电流大小的变化

Fig. 6.  Average width of magnetic islands and magnetic shear as a function of toroidal current ${I_0}$.

图 7  不同电流大小下的庞加莱磁面　(a) ${I_0} = - 1{\text{ kA}}$; (b) ${I_0} = - 3{\text{ kA}}$; (c) ${I_0} = - 5{\text{ kA}}$

Fig. 7.  Poincaré plots of magnetic surfaces with different amplitude of current: (a) ${I_0} = - 1{\text{ kA}}$; (b) ${I_0} = - 3\; {\rm kA}$; (c) ${I_0} = - {\text{5 kA}}$.

图 8  不同反向电流大小所对应的旋转变换剖面, 其中红色线为m/n = 5/2有理面位置

Fig. 8.  Rotational transform corresponding to Gaussian current density profile with different amplitude of current (opposite to the initial current). The red dotted line is $m/n = 5/2$ rational surface.

图 9  平均磁岛宽度随分布峰值的变化, 其中红色虚线为初始磁岛宽度

Fig. 9.  Average width of magnetic islands $\left\langle W \right\rangle $ as a function of radial injection location. The red dotted line is the initial average width of magnetic islands.

图 10  不同分布峰值b所对应的庞加莱磁面　(a) $b = 0.3$; (b) $b = 0.5$; (c) $b = 0.8$

Fig. 10.  Poincaré plots of magnetic surface with different radial injection location: (a) $b = 0.3$; (b) $b = 0.5$; (c) $b = 0.8$.

图 11  不同高斯分布峰值b所对应的旋转变换剖面.

Fig. 11.  Rotational transform corresponding to Gaussian current density profile with different radial injection location b.