Achromatic and isochronous lattice design of P2DT bending section in RAON accelerator

Jin, Hyunchang; Jang, Jiho; Jang, Ha-Young; Hong, In–Sun; Jeon, D.

doi:10.1016/j.nima.2015.05.067

Cited by 13 publications

(7 citation statements)

References 6 publications

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“…We are interested in the upper limit on rocky planet radii so, as an upper limit, the atmospheric composition was assumed to be pure H2 with For the protoatmospheres in this study, that represent up to a few wt. % of the total planetary mass, a reasonable upper limit on surface temperature, and thus the isothermal upper atmospheric temperature, is ~3000 K based on temperature profiles from more complex calculations (Jin et al 2014;Mordasini et al 2012). In addition, on larger planets with H2 dominated atmospheres, cooling from gas expansion and Lyman-alpha radiation in the upper atmosphere likely result in temperatures of ~3000 K in the thermosphere (Murray-Clay et al…”

Section: Methodsmentioning

confidence: 99%

“…Chen & Rogers 2016;Howe & Burrows 2015;Jin et al 2014;Lopez & Fortney 2013;Lopez et 3 al. 2012;Lopez & Rice 2016;Owen & Jackson 2012;Owen & Morton 2016;Owen & Wu 2013, 2016Wolfgang & Lopez 2015).…”

Section: -10mentioning

confidence: 99%

“…Owen and Wu (2013) showed that XUV-driven hydrodynamic escape from low mass planets results in rocky planets less than 1.5 R  , gas-enveloped planets above 2.5 R  , and a lack of planets with intermediate radii. Jin et al (2014) studied several hydrodynamic escape models and found a valley between 1-2.5 R  depending on the orbital distance chosen for their model, below which planets are rocky and above which planets have thick atmospheres, typically of at least a few wt. %.…”

Section: -10mentioning

confidence: 99%

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Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Lehmer

Catling

2017

ApJ

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Recent observations and analysis of low mass (<10 M  ), exoplanets have found that rocky planets only have radii up to 1.5-2 R  . Two general hypotheses exist for the cause of the dichotomy between rocky and gas-enveloped planets (or possible water worlds): either low mass planets do not necessarily form thick atmospheres of a few wt. %, or the thick atmospheres on these planets easily escape driven by x-ray and extreme ultraviolet (XUV) emissions from young parent stars. Here we show that a cutoff between rocky and gas-enveloped planets due to hydrodynamic escape is most likely to occur at a mean radius of 1.760.38 (2) R  around Sunlike stars. We examine the limit in rocky planet radii predicted by hydrodynamic escape across a wide range of possible model inputs using 10,000 parameter combinations drawn randomly from plausible parameter ranges. We find a cutoff between rocky and gas-enveloped planets that agrees with the observed cutoff. The large cross-section available for XUV absorption in the extremely distended primitive atmospheres of low mass planets results in complete loss of atmospheres during the ~100 Myr phase of stellar XUV saturation. In contrast, more massive planets have less distended atmospheres and less escape, and so retain thick atmospheres through XUV saturation and then indefinitely as the XUV and escape fluxes drop over time. The agreement between our model and exoplanet data leads us to conclude that hydrodynamic escape plausibly explains the observed upper limit on rocky planet size and few planets (a "valley" or "radius gap") in the 1.5-2 R  range.

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Section: Methodsmentioning

confidence: 99%

Section: -10mentioning

confidence: 99%

Section: -10mentioning

confidence: 99%

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Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Lehmer

Catling

2017

ApJ

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“…The lattice parameters are same as ones in Ref. [2]. The charge state distribution is obtained by using Baron's formula as explained in the previous section.…”

Section: -Degree Bending Sectionmentioning

confidence: 99%

“…The 5 charge states from 77+ to 81+ of the uranium beams are selected in the bending sections. In this work, we will focus on the 180-degree bending section which was designed to be a second-order achromatic and isochronous in order to minimize the emittance growth through the bending section [2]. In the initial phase of beam commissioning of the linac the carbon stripper will be used and replaced by a liquid lithium target.…”

Section: Introductionmentioning

confidence: 99%

Charge stripper effects on beam dynamics in the 180-degree bending section of the RISP linac

Jang

Jin

Song

2016

Journal of the Korean Physical Society

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The RAON, a superconducting linear accelerator for RISP (Rare Isotope Science Project), will use a charge stripper in order to increase the charge states of the heavy ions for effective acceleration in the higher energy part of the linac. The charge stripper affects the beam qualities by scattering when the heavy ions go through the charge stripper. Moreover we have to select and accelerate proper charge states between 77+ and 81+ for uranium beam case in order to satisfy the beam power requirement at an IF (Inflight Fragmentation) target. This work focuses on the beam optics affected by the charge stripper in the 180-dgree bending section.PACS number: 29.27.Eg,

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Beam dynamics simulations at the high energy accelerator section in the RAON accelerator

Jin,

Jang,

Jang

et al. 2024

J. Korean Phys. Soc.

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Achromatic and isochronous lattice design of P2DT bending section in RAON accelerator

Cited by 13 publications

References 6 publications

Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Rocky Worlds Limited to ∼1.8 Earth Radii by Atmospheric Escape during a Star’s Extreme UV Saturation

Charge stripper effects on beam dynamics in the 180-degree bending section of the RISP linac

Beam dynamics simulations at the high energy accelerator section in the RAON accelerator

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