Upgraded pulsed magnetic field generator for Shenguang-II laser facility toward 30 T

Hu, Peng; Zhao, Jiayi; Wang, Jin-can; Zhang, Zhen-chi; Tang, Hui-bo; Hu, Guang-yue

doi:10.1088/1748-0221/17/07/p07036

Cited by 3 publications

(3 citation statements)

References 45 publications

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“…We also use our radiation simulation to reproduce the POC experiments in the OMEGA EP facility, and the simulation results are very similar to their experimental results, which indicates that the radiation hydrodynamic simulation is reliable in predicting experimental results. Regarding the generation of the magnetic field in the experiment, we plan to use the pulse-power system (Hu et al 2022) for weakly magnetized cases. For mediummagnetized and strongly magnetized cases, we plan to generate magnetic fields using the laser-driven capacitor-coil target method.…”

Section: Discussionmentioning

confidence: 99%

Formation Mechanism of Laser-driven Magnetized “Pillars of Creation”

Lei,

Wang,

et al. 2023

ApJ

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The Pillars of Creation, one of the most recognized objects in the sky, are believed to be associated with the formation of young stars. However, so far, the formation and maintenance mechanism of the pillars are still not fully understood due to the complexity of the nonlinear radiation magnetohydrodynamics (RMHD). Here, assuming laboratory laser-driven conditions, we studied the self-consistent dynamics of pillar structures in magnetic fields by means of two-dimensional and three-dimensional (3D) RMHD simulations, and the results support our proposed experimental scheme. We find that only when the magnetic pressure and ablation pressure are comparable, the magnetic field can significantly alter the plasma hydrodynamics. For medium-magnetized cases (β initial ≈ 3.5), the initial magnetic fields undergo compression and amplification. This amplification results in the magnetic pressure inside the pillar becoming large enough to support the sides of the pillar against radial collapse due to pressure from the surrounding hot plasma. This effect is particularly pronounced for the parallel component (B y ), which is consistent with observational results. In contrast, a strong perpendicular (B x , B z ) magnetic field (β initial < 1) almost retains its initial distribution and significantly suppresses the expansion of blown-off gas plasma, leading to the inability to form pillar-like structures. The 3D simulations suggest that the bending at the head of “Column I” in the Pillars of Creation may be due to nonparallel magnetic fields. After similarity scaling transformation, our results can be applied to explain the formation and maintenance mechanism of the pillars, and can also provide useful information for future experimental designs.

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Section: Discussionmentioning

confidence: 99%

Formation Mechanism of Laser-driven Magnetized “Pillars of Creation”

Lei,

Wang,

et al. 2023

ApJ

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“…图1 给出了实验中激光、靶、磁场和探测设备的设置情况. 我们使用磁场发生装置产生的脉冲大电流在亥姆霍兹线圈中产生峰值约为7 T的准均匀脉冲磁场 [15][16][17] , 磁场峰值持续时间大于200 ns 度的测量发现这种尖刺是平行于磁力线方向发展的槽纹结构 [13,14] , 称为"槽纹不稳定性". 表1列出了真空背景(0.01 Pa)时测量的特征等离子体参数, 其中等离子体温度和抗磁腔被磁场减速时的等效重力加速度参考之前的结果 [13] .…”

Section: 实验设置unclassified

Influence of background gas on flute instability produced at interface between laser plasma and external magnetic field

Zhang,

Tang,

Wang

et al. 2023

Acta Phys. Sin.

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Diamagnetic cavity and flute instability generated by plasma expansion in an external magnetic field are important phenomena in space and fusion physics.We use a nanosecond laser to irradiate a carbon planar target to generate plasma, and at the same time apply a 7T transverse pulsed strong magnetic field to the plasma. The flute instability generated on the surface of the diamagnetic cavity when the plasma expands in an external magnetic field is studied experimentally. Data analysis shows that under our experimental parameters, the radius of gyration of electrons(ρe) is much smaller than the density gradient scale length of the diamagnetic cavity(Ln), while the ion's gyration radius(ρi) is much larger than Ln, indicating that the electrons are magnetized while the ions are non magnetized. The relative drift between electrons and ions provides free energy for the development of instability.The drift velocity is composed of the gravity drift velocity and the diamagnetic gradient drift velocity. The calculation shows that the gravity drift velocity is much larger than the diamagnetic gradient drift velocity in our experiment, so the instability belongs to the Large Larmor Radius Instability. By filling the target chamber with helium, we found that the background gas can significantly inhibit the development of flute instability. When the background gas pressure exceeds 50Pa (about 1% of the interface plasma density), the flute instability is almost is completely suppressed. Kinetic dispersion equations show that ion-ion collisions and electron-ion collision effects are the main factors that inhibit the development of instability. Calculations on the dispersion equation show that ion-ion collisions are the main factor that inhibits the development of instabilities.

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“…It is well known that the only method to generate very high magnetic fields is to drive energy into a fieldgenerating coil wound with special wire (this coil works in all respect as a magnet and will therefore be called in the following the magnet) [1][2][3][4][5][6][7]. A typical example is the discharge of energy previously stored in a capacitor bank: where the duration of the obtained magnetic pulse depends only on the bank capacity and inductance of the magnet, while the maximum generated fields are also function of the total discharged energy.…”

Section: Introductionmentioning

confidence: 99%

Well balanced pick-up assembly for double pulsed magnetic field apparatus

Bolzoni,

Cabassi

2024

Eng. Res. Express

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The generation of high magnetic pulsed fields involves several technological challenges. State-of-the-art fieldpeak intensities can be achieved by means of double-coil systems and, as for other configurations, a specialpick-up system is required to clean the signal from spurious components and artifacts. However, the design of awell-balanced pick-up for double-coil systems is not a trivial task because of the different mutual inductance ofthe two field coils. In general the pick-up can be optimized for one coil only, but not for both.Here we present anew pick-up concept specifically aimed at solving this problem, based on an active compensation bridge and aspecial compensating coil located outside field-generating coils. Besides yielding a good balance of the signalover all pulse duration, a further advantage is an additional increase in the signal-to-noise ratio.

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Upgraded pulsed magnetic field generator for Shenguang-II laser facility toward 30 T

Cited by 3 publications

References 45 publications

Formation Mechanism of Laser-driven Magnetized “Pillars of Creation”

Formation Mechanism of Laser-driven Magnetized “Pillars of Creation”

Influence of background gas on flute instability produced at interface between laser plasma and external magnetic field

Well balanced pick-up assembly for double pulsed magnetic field apparatus

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