Experimental studies of cusp stabilization in Keda Mirror with AXisymmetricity (KMAX)

Li, Qing; Zhu, Guangyan; Ren, Baoming; Ying, Jiacheng; Yang, Zhida; Sun, Xuan

doi:10.1088/2058-6272/ac8e45

Cited by 4 publications

(3 citation statements)

References 31 publications

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“…It is interesting and to some extent unexpected that such a plate, contrary to well-founded fears, did not lead to degradation of plasma parameters, even if it was placed relatively close to the neck of the magnetic plug. Variant z E > 1 simulates a terminal MHD stabilizer of the cusp type [38][39][40][41][42][43].…”

Section: Mhd Stabilization By End Anchorsmentioning

confidence: 99%

Wall stabilization of the rigid ballooning m = 1 mode in a long-thin mirror trap

Kotelnikov¹,

Prikhodko²,

Yakovlev³

et al. 2022

Nucl. Fusion

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The prospect of stabilization of the $m=1$ ``rigid'' ballooning mode in an open axially symmetric long-thin trap with the help of a conducting lateral wall surrounding a column of isotropic plasma is studied. It was found that for effective wall stabilization, the beta parameter $\beta$ must exceed some critical value $\beta_{\text{crit}}$. The dependence of $\beta_{\text{crit}}$ on the mirror ratio, radial pressure profile, axial profile of the vacuum magnetic field, and the width of vacuum gap between plasma and lateral wall was studied. Minimal critical beta at the level of $70\%$ is achieved at zero vacuum gap, although stability zone at $\beta \to 1$ exists even at extremely wide vacuum gap. It is shown that when a conducting lateral wall is combined with conducting end plates simulating attachment of the end MHD stabilizers to the central cell of an open trap, there are two critical beta values and two stability zones that can merge, making stable the entire range of allowable beta values $0<\beta<1$.

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Section: Mhd Stabilization By End Anchorsmentioning

confidence: 99%

Wall stabilization of the rigid ballooning m = 1 mode in a long-thin mirror trap

Kotelnikov¹,

Prikhodko²,

Yakovlev³

et al. 2022

Nucl. Fusion

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show abstract

“…Second, plasma stabilization will be required to enhance plasma performance. Previous studies showed that it was essential to suppress the MHD instabilities for better confinement (England et al 2009;Ryutov et al 2011;Qing et al 2023). In the near future, we will scan the location of the collector to adjust the stability of the interchange mode.…”

Section: Summary and Future Workmentioning

confidence: 99%

“…2011; Qing et al. 2023). In the near future, we will scan the location of the collector to adjust the stability of the interchange mode.…”

Section: Summary and Future Workmentioning

confidence: 99%

Development of a new magnetic mirror device at the Korea Advanced Institute of Science and Technology

Oh,

Choe,

Baek

et al. 2024

J. Plasma Phys.

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A new magnetic mirror machine named KAIMIR (KAIST mirror) has been designed and constructed at the Korea Advanced Institute of Science and Technology (KAIST) to study mirror plasma physics and simulate the boundary regions of magnetic fusion plasmas such as in a tokamak. The purpose of this paper is to introduce the characteristics and initial experimental results of KAIMIR. The cylindrical vacuum chamber has a length of 2.48 m and a diameter of 0.5 m and consists of three sub-chambers, namely the source, centre and expander chambers. A magnetic mirror configuration is achieved by electromagnetic coils with a maximum magnetic field strength of 0.4 T at the mirror nozzles and 0.1 T at the centre. The source plasma is generated by a plasma washer gun installed in the source chamber with a pulse forming network system. The typical discharge time is ~12 ms with a ~6 ms (1–7 ms) steady period. Initial results show that the on-axis electron density at the centre is 1019–20 m−3 and the electron temperature is 4–7 eV. Two parameters were varied in this initial phase, the source power and the mirror ratio, which is the ratio of highest to lowest magnetic field strength in the mirror-confined region. We observed that the increase of the electron density was mitigated for a source power above 0.2 MW. It was also found that the electron density increases almost linearly with the mirror ratio. Accordingly, the stored electron energy was also linearly proportional to the mirror ratio, similar to the scaling of the gas dynamic trap.

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An axisymmetric mirror device for studying confinement and instability

Yang

Zhu

et al. 2023

Review of Scientific Instruments

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We describe a magnetic mirror device, namely, the Keda Mirror with AXisymmetricity (KMAX), which aims to study new approaches to confine and stabilize the mirror plasma as well as basic plasma research. KMAX consists of one central cell, two side cells, and two end chambers at two ends of the device. For the central cell, the mirror-to-mirror distance is 5.2 m, while the central cylinder is 2.5 m in length and 1.2 m in diameter. The plasmas are generated by two washer guns located in the end chambers, which subsequently flow into the central cell and merge there. The density in the central cell is usually adjusted by changing the magnetic field strength inside the side cell, and it ranges from 1017 to 1019 m−3, depending on the experimental requirement. Ion cyclotron frequency heating with two 100 kW transmitters is routinely used to heat up the ions. Plasma controls mainly rely on configuring the magnetic geometry and rotating magnetic fields to improve the confinement and suppress instability. Routine diagnostics, such as probes, interferometers, spectrometers, diamagnetic loops, and bolometers, are also reported in this paper.

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Experimental studies of cusp stabilization in Keda Mirror with AXisymmetricity (KMAX)

Cited by 4 publications

References 31 publications

Wall stabilization of the rigid ballooning m = 1 mode in a long-thin mirror trap

Wall stabilization of the rigid ballooning m = 1 mode in a long-thin mirror trap

Development of a new magnetic mirror device at the Korea Advanced Institute of Science and Technology

An axisymmetric mirror device for studying confinement and instability

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