Electromagnetic field from asymmetric to symmetric heavy-ion collisions at 200 $\mathrm{GeV}/c$

Electromagnetic fields produced in relativistic heavy-ion collisions are affected by the asymmetry of the projectile-target combination as well as the different initial configurations of the nucleus. In this study, the results of the electric and magnetic fields produced for different combinations of ions, namely ${}^{12}\mathrm{C}+{}^{197}\mathrm{Au}$, ${}^{24}\mathrm{Mg}+{}^{197}\mathrm{Au}$, ${}^{64}\mathrm{Cu}+{}^{197}\mathrm{Au}$, and ${}^{197}\mathrm{Au}+{}^{197}\mathrm{Au}$ at $\sqrt{s_{NN}}=200$ GeV, are demonstrated with a multiphase transport model. The configuration of the distribution of nucleons of ${}^{12}\mathrm{C}$ is initialized by a Woods-Saxon spherical structure, a three-$\alpha$-clustering triangular structure or a three-$\alpha$-clustering chain structure. It was observed that the electric and magnetic fields display different behavioral patterns for asymmetric combinations of the projectile and target nuclei as well as for different initial configurations of the carbon nucleus. The major features of the process are discussed.

Figure 1

Proton distribution probability in central (at $b=0$ fm) and peripheral (at $b=8$ fm) ${}^{12}\mathrm{C}+{}^{197}\mathrm{Au}$ collisions due to different configurations of ${}^{12}\mathrm{C}$; (a) Woods-Saxon, (b) chain, and (c) triangular.

Figure 2

Impact parameter dependence of the $x$ component of electric field ($\langle E_x\rangle /m_{\pi }^2$) in the collision systems Au + Au, Cu + Au, Mg + Au, and C + Au. Inset displays $\langle E_x\rangle /m_{\pi }^2$ for different initial configurations of ${}^{12}\mathrm{C}$.

Figure 3

Same as Fig. 1 but for the opposite $y$ component of magnetic field (-$\langle B_y\rangle /m_{\pi }^2$).

Figure 4

Impact parameter dependence of the $x$ component of electric field ($\langle E_x\rangle /m_{\pi }^2$) of projectile and target nuclei of Au + Au, Cu + Au, Mg + Au, and C + Au. Panel (a) is for the projectile and panel (b) is for the target. The insets are for ${}^{12}\mathrm{C}$ + Au for different initial configurations.

Figure 5

Same as Fig. 3 but for the opposite $y$ component of the magnetic field $[\langle B_y\rangle /m_{\pi }^2]$ of projectile and target nuclei as shown in panels (b) and (b), respectively.

Figure 6

Impact parameter dependence of the $y$ component of electric field ($\langle E_y\rangle /m_{\pi }^2$) in panel (a) and the $x$ component of magnetic field ($\langle B_x\rangle /m_{\pi }^2$) in panel (b) of Au + Au, Cu + Au, Mg + Au, and C + Au. The insets are for ${}^{12}\mathrm{C}$ + Au for different initial configurations.

Figure 7

Impact parameter dependence of the square of the electric field ($\langle E^2\rangle /m_{\pi }^4$) in panel (a) and the square of the magnetic field ($\langle B^2\rangle /m_{\pi }^4$) panel (b) of Au + Au, Cu + Au, Mg + Au, and C + Au. The insets are for ${}^{12}\mathrm{C}$ + Au for different initial configurations.