Spheromak flux conserver

The observed tilting is consistent with theoretical predictions which further, predict stability for a sufficiently oblate Spheromak in a flux conserving shell Experiments with oblate flux conservers as shown in Fig. 10, have confirmed the theoretical prediction. Isloated, oblate Spheromak rings are produced which decay stably and have parameters given in Table 2. 

Two types of CTs are studied at Los Alamos Spheromaks and Field Reversed Configurations (FRCs). Spheromaks, which contain both poloidal and toroidal field components, are produced by a magnetized coaxial source (magnetized Marshall gun), as shown in Fig. 1(a). The separated spheromak is trapped and confined in a metal flux conserver not shown in Fig. 1. Coaxial sources, 30 cm in diameter, have been used to form spheromaks in the CTX facility and its predecessor, the Prototype facility. ... 

The formation process shown in Fig, 1(a) results in a spheromak trapped in a flux conserver, as shown in Fig, 5, Field probes measuring all three orthogonal components at several points along the axis of symmetry indicate that field reconnection is complete within less than 50 ys. The axial component of the field... 

Several different flux conserver shapes and external field conditions have been used to test the gross stability of the spheromak. Some of these configurations are shown in Fig, 6, As predicted by theory, the prolate spheromaks produced in the first flux conserver in Fig, 6 were unstable to the n = 1, m = 1 tilting mode (n and m are the toroidal and poloidal mode numbers), but the oblate shape of the other three conservers stabilized the tilt. The addition of external field has a destabilizing influence, but the last flux conserver shown stabilized the plasma even with significant external field. 

Fig. 6. Cross sections of four flux conserver shapes and proximity to the coaxial source. The stability of the spheromak to the tilting mode is indicated as a function of shape and presence of external fields.

---