PEOPLE
Li, Hua-bai / Professor
PHONE: (852) 3943 1118
EMAIL: hbli@cuhk.edu.hk
ORCID: 0000-0003-2641-9240
OFFICE: Room 305, 3/F, Science Centre North Block
Research
Links to publications can be found in the “Selected Recent Publications” section below.
News
The first detection of the ambipolar diffusion scale originates from NGC 6334 (Tang et al. 2018), located in the sting of the Scorpio constellation; thus, we named the code.
4. Impeding Turbulence Decay in Self-gravitating Cloud Cores
The waterfall plot depicts the decay of cloud turbulence with (left) and without (right) self-gravity. In the high-density regions, σv exhibits significantly different fluctuations between the two cases; whereas, in low-density regions it decays steadily and similarly.
Experience it in 3D with full-screen mode using Google Cardboard! (by Andre Chen)
Education
- PhD, Department of Astronomy and Physics, Northwestern University, 2006
Position
- 2025-now, Professor, Department of Physics, The Chinese University of Hong Kong
- 2019-2025, Associate Professor, Department of Physics, The Chinese University of Hong Kong
- 2013-2019, Assistant Professor, Department of Physics, The Chinese University of Hong Kong
- 2009-2013, Postdoctoral Fellow, Max Planck Institute for Astronomy
- 2006-2009, Postdoctoral Fellow, Harvard-Smithsonian Center for Astrophysics
- 2000-2006, Research/Teaching Assistant, Northwestern University
- 1997-1999, Second Lieutenant, Taiwanese Marine Corp
Research Interests
- Star formation
- Interstellar medium turbulence and magnetic fields
- Astronomical instrumentation
Selected Recent Publications
Magnetic fields of molecular clouds
- “Anchoring Magnetic Field in Turbulent Molecular Clouds“, Li, H.-b., Dowell, C. D., Goodman, A., Hildebrand, R. and Novak, G., ApJ 704, 891 (2009).

- “The Alignment of Molecular Cloud Magnetic Fields with the Spiral Arms in M33“, Li, H.-b. and Henning, T., Nature 479, 499 (2011).

- “The Link between Magnetic Fields and Cloud/Star Formation“, Li et al., A Chapter of Protostars and Planets VI, (2014).

- “Anchoring Magnetic Field in Turbulent Molecular Clouds II – from 0.1 to 0.01 Parsec“, Zhang, Y. (Ph.D. student), Guo, Z. (M.Phil. student), Wang H.H. and Li, H.-b., ApJ 871, 98 (2019).

- “A comparison between magnetic field directions inferred from Planck and starlight polarimetry towards Gould Belt Clouds“, Q. Gu & H.-b. Li, ApJL 871, L15 (2019).

- “Magnetic Fields in Molecular Clouds—Observation and Interpretation“, LI, H.-b. Galaxies 2021, 9, 41 (2021).

… and their effects on cloud fragmentation
- “The link between magnetic fields and filamentary clouds: bimodal cloud orientations in the Gould Belt“, Li, H.-b., Fang, M., Henning, T. and Kainulainen, J., MNRAS, doi:10.1093/mnras/stt1849 (2013).

- “Self-similar Fragmentation Regulated by Magnetic Fields in a Region Forming Massive Stars“, Li, H.-b., Yuen K. H., Otto F., Leung P. K., et al., Nature, (2015).

- “The link between magnetic field orientations and star formation rates“, H.-b. Li, H.J. Jiang, X.D. Fan, Q.L. Gu and Y.P. Zhang, Nature Astronomy 1, 0158 (2017).

- “The link between magnetic fields and filamentary clouds II: Bimodal linear mass distributions“, Law C. Y. (M.Phil student), Li, H.-B. and Leung, P. K., MNRAS 484, 3604 (2019).

- “Bayesian Revisit of the Relationship between the Total Field Strength and the Volume Density of Interstellar Clouds“, H.J. Jiang, H.-b. Li, X.D. Fan, ApJ 890, 153 (2020).

- “The links between magnetic fields and filamentary clouds III: field regulated mass cumulative functions“, Law C. Y. (M.Phil student), Li H.-B., Cao Z. (Ph.D. student) and Ng C.-Y., MNRAS 498, 850 (2020).

- “Turbulence in Zeeman Measurements from Molecular Clouds“, Zhuo Cao (Ph.D. student) and Hua-bai Li, ApJL, 946, L46 (2023)

… and their effects on gas motion (turbulence)
- “Evidence of Dynamically Important Magnetic Fields in Molecular Clouds“, Li, H.-b., Blundell, R., Hedden, A., Kawamura, J., Paine, S. and ong, E., MNRAS 411, 2067 (2011).

- “Velocity Anisotropy in Self-gravitating Molecular Clouds. I. Simulation“, Otto, F. ( Postdoc), Ji, W. (exchange student) and Li, H.-b., ApJ 836, 95 (2017).

- “Velocity Anisotropy in Self-gravitating Molecular Clouds. II. Observation“, Luk, S.-S. (M.Phil student), Li, H.-b., and Li, D., ApJ 928, 132 (2022).

- “Impeding Turbulence Decay in Self-gravitating Cloud Cores“, Yuan, S. (Ph.D. student) and Li, H.-b., ApJ, 988, 132 (2025).

Turbulence Induced Ambipolar Diffusion
- “Probing the Turbulence Dissipation Range and Magnetic Field Strengths in Molecular Clouds“, Li, H.-b. and Houde, M., ApJ 677, 1151 (2008).

- “Tracing Turbulent Ambipolar Diffusion in Molecular Clouds“, Li, H.-b., Houde, M., Lai, S. and Sridharan, T. K., ApJ 718, 905 (2010).

- “Probing the Turbulence Dissipation Range and Magnetic Field Strengths in Molecular Clouds II. Directly Probing the Ion-neutral Decoupling Scale“, Tang, K.S. (M.Phil student), Li, H.-b. and Lee, W-K, ApJ 862, 42 (2018).

- “Scorpio: a two-fluid code for ambipolar diffusion simulations informed by recent observational constraints“, Cheng, H. L. (Ph.D. student) et al., RASTI, 2025.

Instrumentation
- “Design and Initial Performance of SHARP, a Polarimeter for SHARC-II Camera at the Caltech Submillimeter Observatory“, Li, H.-b., Dowell, D., Kirby, L., Novak, G. and Vaillancourt, J., Applied Optics 47, 422 (2008).
- “Atacama sub-millimeter telescope experiment polarimeter (APol) I: design and lab-test result“, Y. Zhang, H.-B. Li, D. Lühr, T. Takekoshi, T. Oshima and Q. Gu, Applied Optics 59, 2593 (2020).
- “A control system for the ASTEPolarimeter: design and testing“, Lühr Sierra, Melillanca, Vargas and H.-B. Li, Proc. SPIE 11452, Software and Cyberinfrastructure for Astronomy VI, 1145237 (2020).
- “Laser-based frequency-to-pixel mapping method for submillimetre MKID array“, Lyu, W. (Postdoc), Li, H.-b., Zhi, Q., Li, J., Shi, S., RASTI, Volume 5, rzag007 (2026).

Press Release
- Homegrown cosmic camera to snap the invisible in stardust, CUHK
- CUHK Physicist and Statistician Work Together to Reveal Link Between Magnetic Fields and Birth Rate of Stars, CUHK
- CUHK Physicist Unveils Mystery of Massive Star Formation, CUHK
- As Stars Form, Magnetic Fields Influence Regions Big and Small, Harvard-Smithsonian Center for Astrophysics
- Magnetic fields set the stage for the birth of new stars, Max-Planck-Institut für Astronomie
- Stellar midwives, Max-Planck-Gesellschaft
- Magnetic Fields in Interstellar Clouds, Harvard-Smithsonian Centerfor Astrophysics Weekly Science Update
- Magnetic Fields Play Larger Role in Star Formation than Previously Thought, Harvard-Smithsonian Center for Astrophysics
Research in the Media (Examples):
- 跨校團隊研製「ROGer」相機 盼解恒星誕生之謎, 文匯報
- 中大揭磁場催生「巨星」, 文匯報
- Cosmic magnetic fields act as ‘birth control’ for stars, Hong Kong and US scientists discover, South China Morning Post
- Even though cosmic magnetic fields are much weaker than Earth’s magnetic field, they have an important effect in regulating how stars form, Astronomy Magazine
- Anziehende Geburten im All, Frankfurter Allgemeine
- Magnetic Fields May Rock Cosmic Cradles for Unborn Stars, Space.com
- Magnetic Fields Guide Star Birth, Space.com
- Magnetic Fields Set Stage for Birth of New Stars, Science Daily
- Birth Control for Stars, Science Now








